Polymers with high internal free volume

ABSTRACT

Shape-persistent organic materials, including polymers, with large degrees of interior free volume are described, along with behaviors and phenomena enabled by their unique properties. One class of such a material is built up from triptycene base moieties wherein three benzene rings are bridged together about a [2.2.2] tricyclic ring system. These units can be assembled into discreet molecules and polymers. These materials and/or formulations thereof with liquid crystals or polymers are useful for the complexation of chemicals and/or polymers; they have very low dielectric constants for use as coatings in dielectric circuits, they provide additional ordering mechanisms in liquid crystals, and they display unusual mechanical responses when subjected to electrochemical, chemical, or mechanical stimuli.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.09/935,060, filed Aug. 21, 2001, now U.S. Pat. No. 6,783,814 whichclaims benefit under 35 U.S.C. §119(e) of priority to ProvisionalApplication Ser. No. 60/226,506, filed Aug. 21, 2000, both of which areincorporated herein by reference.

GOVERNMENT FUNDING

This invention was made with government support under Contract NumberDABT63-97-C-0008, awarded by the Army and Grant Number N00014-97-0174awarded by the Navy. The government has certain rights in the invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to organic/polymer chemistry,and more particularly to molecules such as polymers, that canincorporate triptycenes and iptycenes.

2. Description of Related Art

Many materials and molecules have rigid structures that can be said tobe shape-persistent. Aromatic, conjugated and polycyclic structures aretypically their principle building blocks, and are the basearchitectures that provide the anisotropic characteristics of liquidcrystals and high strength polymers. In general, these materials haveflat two-dimensional structures and low degrees of internal free volume.

In contrast, chemical structures that have relatively high internal freevolumes include those of the iptycenes. Typical applications ofiptycenes and related structures have been as groups to preventaggregation of polymers, thermally stable elements in structuralpolymers, and as a rigid scaffolds to define a molecular receptor.

SUMMARY OF THE INVENTION

The invention comprises materials, compositions and methods that have,as one element, a shape-persistent material with a high degree ofinternal free volume. In another aspect, the invention comprises newmaterials, or known shape-persistent materials with high degree ofinternal free volume that are used in new ways.

In one embodiment, the invention provides a composition comprising aladder polymer or an oligomer that comprises an iptycene.

In another embodiment, the invention provides a composition comprisingan iptycene, having a molecular weight in excess of 2,000 daltons. Thecomposition comprises a shape-persistent molecule containing bridgeheadatoms, with molecular structures radiating from the bridgehead atoms inthree directions and extending outwardly therefrom such that eachdefines a van der Waals contact of furthest point from the bridgeheadatoms of no less than 3.5 Å. The composition can be a linear polymer ora ladder polymer. In one embodiment, the composition is arranged as adielectric material in an electronic component. When the compositiondefines a polymer, the polymer can include a backbone having backboneatoms bonded to other backbone atoms, where bonds involving the backboneatoms are not freely rotatable.

The compositions described herein have a high degree of free volume, forexample, at least 20%, 30%, 50%, 70% or 90% free volume, as definedbelow. Shape-persistent molecules with higher free volume can be used toimprove alignment or orientation of one molecule to another. A varietyof exemplary structures, both of polymeric shape-persistent molecules ormonomers that can be used alone or can be polymerized to form polymersare described herein. It is to be understood that all examples ofmonomers and/or polymers described herein can be used in connection withany aspect or embodiment of the invention in which a shape-persistentmolecule or polymer is desirable.

Where polymers of the invention are provided, they can comprise polymerchain units including chemical functionality allowing the formation ofgrafts. One polymer includes a grafted polymer including iptycene ornon-iptycene units grafted onto polymer chains. Or, iptycene andnon-iptycene units can be used in combination in such a graft polymer.Polymers can be formed of monomer units, each including two reactivesites, one of which has reacted with another monomer unit to form thepolymer backbone, and another of which is available for grafting afterformation of the polymer.

As noted, high free-volume, shape-persistent structures can be used asdielectrics. Dielectric structures having a dielectric constant of about1.9 or less, preferably 1.7, 1.5 or 1.2 or less are provided inaccordance with the invention.

The invention provides negative Poisson ratio (NPR) materials. One setof materials includes polymeric shape-persistent structures having smallpores, on the order of 3-6 Å in size, through which a second polymericmaterial can be threaded to form an interpenetrating network. Forexample, polyiptycenes will form porous materials, as described below,and a generally planar structure perpendicular to the pores. Where aflexible polymer interpenetrates pores of such structures, applyingtension to the interpenetrating polymer can cause the polyiptycenes toalign in a generally planar/planar fashion, causing a greater degree oforder between generally planar polyiptycene structures, therebyincreasing the free volume of the overall structure. This can define aNPR material. That is, when tension is not applied to theinterpenetrating polymer, the generally planar polyiptycene structuresare allowed to rotate or otherwise orient themselves in a low-energy,random configuration. This will tend to minimize free volume. Whentension is applied to the interpenetrating polymer, the generally planarpolyiptycene structures will be moved into alignment generally parallelto each other, forming a higher-energy, higher free-volume structure.The interpenetrating polymer can be, for example, a conjugated polymer,an elastomer, or the like.

In another aspect, the invention comprises a first component comprisinga first, porous shape-persistent polymeric component, and a secondpolymeric component forming an interpenetrating network. The networkpermeates the pores of the first polymeric component.

As mentioned above, shape-persistent molecules of the invention canassist in alignment or orientation of one molecule to another. This canbe important in optical technology, such as liquid crystal display (LCD)technology. Liquid crystals are molecules which, when non-aligned witheach other, are generally transparent. When an electric field isapplied, they can be made to orient in alignment with each other,becoming opaque. Color LCD displays include liquid crystal molecules inconjunction with chromophores, including dyes. Contrast in color LCDdisplays is maximized (a significant advantage) when chromophores can bemade to align with LCD molecules. The present invention involvesincluding a shape-persistent molecule in conjunction with a chromophorein a LCD matrix. The shape-persistent molecule can assist the alignmentof the chromophore with LCD molecules. For example, a shape-persistentmolecule with a high degree of free volume can be covalently attached toa dye and combined with LCD molecules. When energy is applied to thesystem which generally causes LCD molecules to align with each other,the shape-persistent molecule can interact with the LCD molecules tomaximize alignment of the dye with the LCD molecules. This is describedin greater detail below and demonstrated in the examples section. Thisincrease in alignment between two molecules with the assistance of ashape-persistent molecule can be used in essentially any arrangement inwhich improved alignment is desired, not limited to LCD systems.

Accordingly, in one embodiment the invention provides a compositionincluding a chromophore, a shape-persistent molecule having at least 20%free volume, and a host material within which the shape-persistentmolecule self-orients. The host material can be, for example, LCDmolecules.

In another embodiment, the invention involves a method comprisingproviding a first molecular species in association with ashape-persistent molecule having a high degree of internal free volume,and a second molecular species. The method involves causing a change inorientation of the second molecular species and allowing theshape-persistent molecule to thereby alter the orientation of the firstmolecule in response to the change in orientation of the secondmolecule. An example of this involves a second molecular speciescomprising LCD host material and a first molecular species comprising adye covalently bonded to an iptycene. A change in orientation of the LCDhost material (e.g., alignment) causes a change in orientation of thedye as directed by the iptycene, namely, the dye can orient in alignmentwith the LCD host material. Translation, as well as or instead oforientation, can be affected in this manner as well.

Shape-persistent molecules of the invention typically include at leasttwo aromatic rings, each parallel to a common axis in a lowest energystate of the composition.

In another embodiment, the invention comprises a composition including aplurality of liquid crystalline species. Each has a primary axis alignedso as to together define an average axis of the liquid crystallinespecies primary axes. A plurality of chromophores are provided, eachhaving a primary axis aligned so as to together define an average axisof the chromophore primary axes. The alignment of the individualchromophores relative to the average axis of the chromophore primaryaxes includes less variation than the alignment of the individual liquidcrystalline species relative to the average axis of the liquidcrystalline species primary axes.

In another embodiment, the invention provides a size-exclusion article.As used herein, “size-exclusion article” defines a material that willallow the passage of species of a particular size, but not allow passageof species larger than that size. Examples include filters, such aszeolite structures, etc. Size-exclusion articles of the invention can bedefined by any species described herein that will form pores, such as aladder polymer or oligomer comprising an iptycene, having pore sizesnoted herein.

Compositions of the invention can enhance the modulus of polymericcompositions. This can be effected by blending compositions of theinvention into existing polymer blends, forming copolymers, includingcompositions of the invention, or grafting compositions of the inventiononto existing polymers. Accordingly, one composition of the inventionincludes a first component that is a polymer including an iptycene, anda second component. The second component typically is a high molecularweight linear polymer, such as one having a molecular weight greaterthan 5,000, 10,000 or 20,000 daltons. The composition has a greaterstrength compared to a composition that is identical, with the exceptionthat it does not include the iptycene-containing polymer.

In another aspect, the invention comprises a chromophore and ashape-persistent molecule including at least two aromatic rings, eachparallel to a common axis in a lowest energy state of the composition.

In another aspect, the invention comprises a composition comprising ashape persistent moiety with a high degree of internal free volume and achromophore.

Other advantages, novel features, and objects of the invention willbecome apparent from the following detailed description of the inventionwhen considered in conjunction with the accompanying drawings, which areschematic and which are not intended to be drawn to scale. In thefigures, each identical, or substantially similar component that isillustrated in various figures is represented by a single numeral ornotation. For purposes of clarity, not every component is labeled inevery figure, nor is every component of each embodiment of the inventionshown where illustration is not necessary to allow those of ordinaryskill in the art to understand the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred, non-limiting embodiments of the present invention will bedescribed by way of example with reference to the accompanying drawingsin which:

FIG. 1A illustrates structural diagrams of prior art triptycene;

FIG. 1B illustrates structural diagrams of molecules of prior art;

FIG. 1C illustrates structural diagram of molecules of prior art;

FIG. 1E illustrates example dienes useful in forming molecules inaccordance with the invention;

FIG. 1F illustrates example dienophiles useful in forming molecules inaccordance with the invention;

FIG. 1G is a structural diagram of a molecular structure useful inaccordance with several embodiments of the invention in whichbridgeheads can be carbon or nitrogen;

FIG. 1H is a molecule of one embodiment of the invention;

FIG. 1J show molecules of one embodiment of the invention;

FIG. 1K show molecules of one embodiment of the invention;

FIG. 1L show molecules of one embodiment of the invention;

FIG. 1M show molecules of one embodiment of the invention;

FIG. 1N show molecules of one embodiment of the invention;

FIG. 2 illustrates the structure of one embodiment of the invention,specifically, a ladder polymer comprising an iptycene;

FIG. 2A illustrates linkages for use in one embodiment of the invention;

FIG. 2B illustrates a sample triptycene;

FIG. 2C illustrates iptycenes as used in a polymer according to oneembodiment of the invention;

FIG. 2D illustrates iptycenes as used in a polymer according to anotherembodiment of the invention;

FIG. 2E illustrates synthetic reaction scheme of iptycenes polymersaccording to one embodiment of the invention;

FIG. 3 illustrates alignment of a triptycene with liquid crystalmolecules according to one embodiment of the invention;

FIG. 4 illustrates molecules useful in accordance with embodiments ofthe invention;

FIG. 5 is a plot of the dichroic ratio of a dye comprising an iptycenealigning with a liquid crystal composition compared with a dye that doesnot include an iptycene according to one embodiment of the invention;

FIG. 6 is a plot of the dichroic ratio of iptycene containing dye versusiptycene-free dye in terms of alignment with liquid crystals accordinganother embodiment of the invention;

FIG. 6A illustrates a synthetic reaction scheme of one embodiment of theinvention;

FIG. 6B illustrates a synthetic reaction scheme of another embodiment ofthe invention;

FIG. 6C illustrates a synthetic reaction scheme of another embodiment ofthe invention;

FIG. 6D illustrates a synthetic reaction scheme of another embodiment ofthe invention;

FIG. 6E illustrates a synthetic reaction scheme of another embodiment ofthe invention;

FIG. 6F illustrates a synthetic reaction scheme of another embodiment ofthe invention;

FIG. 7 illustrates structural diagrams of molecules of the invention;

FIG. 8 illustrates UV-visible light spectra of dyes comprising variousmolecules in conjunction with liquid crystal compositions illustratingincreased alignment with increased iptycene content (specifically,molecules illustrated in FIG. 7), in accordance with the invention;

FIG. 9 illustrates UV-visible light spectra of molecules of theinvention with dyes also illustrating improved alignment with liquidcrystals;

FIG. 9A illustrates a synthetic reaction scheme of one embodiment of theinvention;

FIG. 9B illustrates a synthetic reaction scheme of another embodiment ofthe invention;

FIG. 9C illustrates a synthetic reaction scheme of another embodiment ofthe invention;

FIG. 9D illustrates a synthetic reaction scheme of another embodiment ofthe invention;

FIG. 9E illustrates a synthetic reaction scheme of another embodiment ofthe invention;

FIG. 9F illustrates a synthetic reaction scheme of another embodiment ofthe invention;

FIG. 9G illustrates a synthetic reaction scheme of another embodiment ofthe invention;

FIG. 9H illustrates a synthetic reaction scheme of another embodiment ofthe invention;

FIG. 10 is a plot of absorption spectra of molecules of the inventionillustrating enhanced alignment with liquid crystals through the use ofiptycenes; and

FIG. 11 is a plot of fluorescence spectra of molecules of the inventionsimilarly illustrating enhanced alignment with liquid crystals via theuse of shape-persistent, high-free volume molecules.

DETAILED DESCRIPTION

The present invention provides new shape-persistent molecules with highinternal free volume, and new uses and compositions based on these andpreviously known high internal volume shape-persistent molecules.

A “shape-persistent molecule,” as used herein, is a molecule with asignificant amount of rigid structure, as is understood by those ofordinary skill in the art. Preferably, in a shape-persistent molecule,no portion of the molecule having a combined molecular weight of atleast 15 g/mol may move relative to other portions of the molecule viarotation about a single bond. In other embodiments of shape-persistentmolecules, no portion of the molecule having a molecular weight ofgreater than 25, 50, or 100 g/mol can move relative to other portions ofthe molecule via rotation about a single bond. Rigid structures may beprovided, for example, by aromatic rings, cyclic structures, cyclicaromatic structures, and the like. For example, molecular structure 1 inFIG. 1A, representing triptycene, is shape-persistent, with a highdegree of internal-free volume. As a comparative example, a moleculeincluding a cyclic structure such as a benzene ring connected to anotherportion of the molecule via only a single bond, has at least a portionof the molecule that is not shape-persistent according to the embodimentin which the shape-persistent molecule includes no portion having amolecular weight of at least that of a benzene ring that can moverelative to other portions of the molecule via rotation about a singlebond.

Many of the shape-persistent structures of the invention, and used intechniques of the invention, may belong to the class of polymers andmolecules built up from structure 1, known as the iptycenes. Iptycenesand like molecules have previously been reported in, for example, Hart,“Iptycenes, Cuppendophanes and Cappedophanes,” Pure and AppliedChemistry, 65(1):27-34 (1993); or Shahlia et al., “Synthesis ofSupertriptycene and Two Related Iptycenes,” Journal of OrganicChemistry, 56:6905-6912 (1991). Triptycene 1 as shown in FIG. 1A is9,10-[1′,2′-benzeno]-9,10-dihydroanthracene. Iptycenes are a class ofcompounds based off this base triptycene structure, where the prefixindicates the number of separated arene planes. Examples of iptycenesinclude triptycenes (3 planes) and pentiptycenes (5 planes). The areneplanes are fused together at the [2.2.2]bicyclooctane junctions. Thearene planes are not limited to benzene rings; they may be anypolycyclic aromatic structure.

Various embodiments of the invention involve use of molecules comprisingan iptycene, such as a triptycene. It is to be understood thatstructures comprising an iptycene include oligomers, polymers, andmonomers. Polymers or oligomers comprising an iptycene can include thosehaving a non-iptycene backbone with iptycene pendent groups or thosehaving iptycenes that form part of the backbone. As an example of thelatter class, a polymer can be made up of monomer iptycene buildingblocks that together form a ladder polymer.

The “internal free volume” or “free volume” of a molecule is defined asthe volume in space taken up by a molecule, where boundaries definingthe internal free volume span all projections or protrusions of themolecule. By way of illustration, a representation 200 in FIG. 1A of theshape-persistent molecule triptycene is shown next to molecularstructure 1 of triptycene. The side-view representation 200 showsinternal free volume 205 as the space defined within boundaries thatspan all extended portions of the molecule.

Shape-persistent molecules may be considered to have a length, width,and thickness. These dimensions may be considered to span an imaginarybox which the molecule, as defined by its van der Waals volume, mayrest. The molecule may be positioned within the box, in relation to aset of x, y, and z axes, such that the shortest axis in the arrangementdefines the molecule's thickness. The minimum thickness of a planarshape-persistent molecule may be defined as the distance between theportions of the molecule located above and below a plane within whichthe molecule can be defined (or which can be contained completely withinthe molecule), for example a plane defined by the carbon nuclei ofbenzene ring. For example, in a benzene ring, the van der Waals radiifor the carbon atoms is about±1.9 Å. A second example is a molecule suchas [2.2.2]bicyclooctane, where the thickness of the molecule would bemeasured from the van der Waals contacts of the outer hydrogen atoms, orabout 5.54 Å.

While these examples may have shape-persistent structures, it should beunderstood that these structures do not define the internal free volume.Rather, the internal free volume is defined by the volume in space takenup by the molecule, where boundaries defining the internal free volumespan all projections or protrusions of the molecule. This can be easilyunderstood with reference to FIG. 1A. It is noted that the internal freevolume need not be totally enclosed. For example, internal free volume205 in FIG. 1A is not totally enclosed. A combination of enclosed andopen volumes in structures together can define free volume within thescope of the invention. The interior free volumes of such structures maybe defined by objects that have an external plane that may be directedalong one axis. Another architecture is one in which the internal spaceof the object may further be enclosed by additional objects, forexample, objects having a concave surface. This may create an evengreater delineation between internal and external space.

In one set of embodiments of the invention, shape-persistent materialsof the invention have a minimum height or length of approximately 6.214Å, a value based on the distance between the van der Waals contacts ofthe 1 and 4 hydrogen atoms of a benzene ring. In one set of embodiments,molecules of the invention include bridgehead atoms and the minimumdistance that a molecule may extend in height or length from abridgehead is 3.5 Å. In other embodiments, the minimum distance that amolecule may extend in height or length from a bridgehead is 4.0 Å, 4.5Å, 5.0 Å, 5.5 Å, 6.0 Å, or 6.2 Å. Each bridgehead may be any suitableatom, for example, a carbon or a nitrogen atom. By way of illustration,molecules 210 and 215 in FIG. 1B do not meet the requirement of a heightor length of approximately 6.214 Å. Molecule 210 has a height of about3.26 Å, as measured from the plane of the benzene ring to the uppermosthydrogen atoms, or a height of about 2.50 Å, as measured from thehydrogen atom attached to bridgehead 220. Molecule 215 has a height ofabout 2.29 Å, as measured from the plane of the benzene ring to theoxygen atom, or a height of about 2.13 Å, as measured from the hydrogenatom attached to bridgehead 220.

In some embodiments, the length of the molecule may be at least twicethe height of the molecule. The longer dimension may lie on atwo-dimensional plane normal to that height. Other three-dimensionalstructures may also be built up from these two-dimensional structures.

Molecules of the invention, in preferred embodiments, have at least 20%free volume; preferably at least 30%, more preferably at least 50% freevolume, more preferably greater than 70% free volume, and mostpreferably greater than 90% free volume.

Techniques for determining free volume may include determining thedensity of the rigid shape-persistent molecule itself, without solvent,and without other, like molecules or different molecules dispersedwithin the material to take up some of the free volume. Alternatively,or where this is impossible, free volume may be deduced from densitymeasurements. For density measurements for determination of free volume,the density may be compared with a solvent of similar composition.Determination of free volume from density measurement may be carried outin a straightforward manner by those of ordinary skill in the art. Forexample, most hydrocarbons have a density between 0.7 g/ml and 0.9 g/ml,and many polymers have densities of about 0.8 g/ml; hence, lowerdensities may be indicative of free volume. For example, a density of0.4 g/ml may indicate a free volume of about 50%.

As most flexible materials will adopt a structure that may minimize freevolume, to maintain high free volume, the precise nature of the rigidshape-persistent structure may be important. Preferred shape-persistentstructures used in the invention may minimize the interpenetration ofshape-persistent structures into each other's free volume. Suchinterpenetration may decrease the net internal free volume.

In one aspect of the invention, known rigid shape-persistent structureswith high degrees of free volume may be used to create new methods forthe alignment of guest molecules or polymers in host polymers and liquidcrystals. In one embodiment, a molecule with anisotropic opticalproperties also comprises a shape-persistent molecule such as aniptycene. For example, structure 1 in FIG. 1A, or structures 2, 3, 4, or5 of FIG. 1C, can be appended onto dye molecules and confer upon themspecial organizational properties. Any shape-persistent molecule havingan internal free volume may be appended onto dye molecules. Theshape-persistent material may be composed of, for example, smallmolecules or high molecular weight polymers. The shape-persistentmaterial may be attached within a main polymer chain or pendant to aflexible or rigid molecule or polymer. In some embodiments,shape-persistent structures may be connected to each other by a polymerinterconnect that can occupy some or most of the free volume of theshape-persistent structure, but may not necessarily be chemicallyattached to the shape-persistent structure. The choice of structure maydepend upon the application. In some embodiments, the shape-persistentstructure may be required to have high thermal stability. In otherembodiments, the shape-persistent structure may require the structuresor formulations to comprise fluorescent or electroactive groups.Accordingly, in this aspect the invention involves shape-persistentmolecules, such as iptycenes, used in conjunction with molecules withanisotropic optical properties such as liquid crystal and dyes. Theshape-persistent molecules typically are bonded to dyes and thiscombination is used in conjunction with a liquid crystal composition.The shape-persistent molecule enhances alignment of the dye with theliquid crystal matrix. The shape-persistent molecular arrangements mayalso include polymers or oligomers. As used herein, “oligomer” is apolymeric species with less than 8 repeat units.

In one set of embodiments of the present invention, compositions of theinvention comprising iptycenes are provided that may have averagemolecular weights greater than 2000 grams/mole (“daltons”), preferablygreater than 2500 daltons, and more preferably greater than 3000, 4000,or 5000 daltons. The materials may be soluble in common solvents, forexample, selected from the group consisting of water, chloroform, carbondioxide, toluene, benzene, hexane, dichloromethane, tetrahydrofuran,ethanol, acetone, and acetonitrile. The materials may be soluble in aleast one of the solvents, or at least two, or three of any of thesesolvents. “Soluble” in this context means soluble at greater than 0.5mg/ml, preferably greater than 1 mg/ml, more preferably greater than 5mg/ml, and more preferably still greater than 10 mg/ml. The materials ofthe invention may also be preferably soluble in common liquid crystals(“LC”) such as cyano-biphenyls, bicyclohexyls, or cyclohexylphenyls, andmay be miscible with common polymers such as polyethylene, polyvinylchloride, poly(methyl methacrylate), polydimethylsiloxane, polyimides,polyisoprene, polypropylene, polystyrene, and co- and block polymersthat include these.

One structural feature of one set of embodiments of the invention, theiptycenes, is that the [2.2.2]bicyclic ring system forms theintersections of planes defined by aromatic rings.

Another class of molecules of the invention are those molecules thatinclude a [2.2.2]bicyclic ring system, with each branch of the systemconnecting to cyclic aromatics. Each of the bridgeheads in thesemolecules may be connected to three cyclic aromatics, and at least oneof the cyclic aromatics may be connected to another [2.2.2]bridgehead-pair of center, or may be fused to another aromatic system(shares at least one bond in common with another aromatic system).

In some embodiments, at least two of the cyclic aromatics emanating fromthe central [2.2.2]system may be fused to another aromatic system orconnected to another [2.2.2]center, and in other embodiments, all threecyclic aromatics may be fused to other aromatic systems or connected toa bridgehead center. For example, dienes, such as those shown in FIG.1E, may emanate from bridgehead centers of various molecules of theinvention. Also, dienophiles, for example, as shown in FIG. 1F, mayemanate from bridgehead centers. Those of ordinary skill in the art willrecognize that, using selected dienes, such as those illustrated in FIG.1E, or selected dienophiles, such as those shown in FIG. 1F, additionalsyntheses may result in any of a wide variety of shape-persistent, highfree volume molecules.

In one set of embodiments shape-persistent, high-free-volume moleculesare based upon structures disclosed in International Patent PublicationWO 99/57528, published Nov. 11, 1999 and incorporated herein byreference. Specifically, with reference to FIG. 1G, structures may beprovided in which G, H, I an J are aromatic groups; d=1 or 2; and d¹=0or 1, such that when d¹=0, d²=0, and when d¹=1, d²=0 or 1. Preferably, cis less than about 10,000.

In a preferred embodiment, G and H may be the same or different, andeach may be selected from the aromatic group consisting of:

I and J may be the same or different and each can be selected from thegroup consisting of:

Any hydrogen in G, H, I and J may be substituted by R², where R² can beselected from the group consisting of C₁-C₂₀ alkoxy, phenoxy, C₁-C₂₀thioalkyl, thioaryl, C(O)OR³, N(R³)(R⁴), C(O)N(R³)(R⁴), F, Cl, Br, NO₂,CN, acyl, carboxylate and hydroxy. R³ and R⁴ may be the same ordifferent, and each may be selected from the group consisting ofhydrogen, C₁-C₂₀ alkyl, and aryl. Z¹ may be selected from the groupconsisting of O, S and NR⁸ where R⁸ can be selected from the groupconsisting of hydrogen, C₁-C₂₀ alkyl, and aryl. Z² may be selected fromthe group consisting of F, Cl, OR³, SR³, NR³R⁴ and SiR⁸R³R⁴.

A may be any shape-persistent molecule such as a cyclic aromatic. A canbe similar to or identical to a branch G, H, I, or J, as shown in FIG.1G, or it may be any other shape-persistent structure described herein.A single branch of G, H, I, J of FIG. 1G may be used in combination withany other shape-persistent organic structure described herein and joinedat a bridgehead center.

Bicyclic ring systems of the invention may be produced via synthesisusing the Diels-Alder reaction. Other structures may be used in certainembodiments in the invention, for example, ladder polymers or ribbonstructures, which each may contain rigid aromatic rings systems. Theseand related structures may be used in combination with other features ofthe invention, such as attachment to dyes, “bundling” of molecules, andthe like. As used herein, a “ladder” polymer is a polymer having abackbone that can only be severed by breaking two bonds.

In one embodiment of the invention, molecules for use in the formationof rigid shape-persistent polymers with high degrees of internal freevolume may involve substitution about the bicyclic ring system, whichmay provide the needed geometry to provide internal free volume in thestructure. In some embodiments of the invention, rigid shape persistentpolymers with high degrees of internal free volume may be provided inwhich the distance from the bridgehead atom to the van der Waals contactof the most distant atom of the smallest substituent directly attachedto the bridgehead carbon is more than 4 Å, preferably 5 Å, 6 Å, or 7 Å,or even greater. The significance of this group is that it serves todefine additional free volume and internal surfaces, from whichimportant organizational properties in conjunction with polymers andliquid crystals may be optimized. The larger groups further providestructures with greater shape persistence, since the polymers may not beeasily collapsed and prevent the interpenetration of one polymer intoanother.

Larger molecules based upon the triptycene structure are callediptycenes. Their polymers are called polyiptycenes, for example,structure 225 in FIG. 1H. Central to this aspect of the invention is theformation of rigid structures which cannot collapse on themselves (i.e.,collapse to a structure having a free volume of approximately zero), andhave a short axis with a distance no less than the long dimension of asingle benzene ring (or its “width,” approximately 6.214 Å, asillustrated as width 230 in FIG. 2). FIGS. 1J, 1K, 1L, 1M and 1N showadditional polyiptycene structures contemplated in the presentinvention. The structures shown in these figures are not intended to belimiting with regard to the scope of the invention.

In all of the figures, R, R′, and R″ can be the same or different.Preferably, R is H or a hydrocarbon group (including cyclic hydrocarbongroups), optionally interrupted by hetero groups. As used herein,“hydrocarbon” is meant to include alkyl, alkenyl, alkynyl, cycloalkyl,aryl, alkaryl, aralkyl, and the like. Hetero groups can include —O—,—CONH—, —CONHCO—, —NH—, —CSNH—, —CO—, —CS—, —S—, —SO—, —(OCH₂CH₂)_(n)R(where n=1-10), —(CF₂)_(n)— (where n=1-10), olefins, and the like. Asused herein, the terms “hydrocarbon,” “alkyl,” “cycloalkyl” and similarhydrocarbon terminology is meant to include alcohols and hydrogen.Examples of such groups are methyl, propenyl, ethynyl, cyclohexyl,phenyl, tolyl, benzyl, hydroxyethyl and the like. R is preferablyselected from groups including hydrogen and the general class of loweralkyl compounds such as methyl, ethyl, or the like.

For example, R can be an alkyl group, preferably having 1 to 24 carbonatoms, more preferably 1 to 18 carbon atoms; an alkenyl group,preferably having 2 to 4 carbon atoms; an aminoalkyl group, preferablyhaving 1 to 8 carbon atoms, and optionally substituted on the nitrogenatom with one or, preferably two alkyl groups, preferably having 1 to 4carbon atoms; an alkyl group, preferably having 1 to 4 carbon atoms,having a five- or six-membered heterocyclic ring as a substituent; anallyloxyalkyl group, preferably having up to 12 carbon atoms; analkoxyalkyl group, preferably having a total of 2 to 12 carbon atoms; anaryloxyalkyl group, preferably having 7 to 12 carbon atoms; an aralkylgroup, or the like.

One polyiptycene structure is illustrated in FIG. 2 as line schematic235, where each line segment represents the side view of an aromaticring. A top view 240 and a side view 245 of a space-filling model of thepolyiptycene structure may also be seen in FIG. 2. It is noted that theline schematic 235 and view 240 are each taken in the same orientationof the molecule. The polymer structure, which may be stereo-irregular,has a number of clefts 150 that can easily bind small molecules as wellas polymer chains.

In some embodiments of the invention, shape-persistent molecules of thepresent invention may have high free volume and high thermal stability.Molecules with these characteristics may be useful in dielectriccoatings for semiconductor devices. By using a low dielectric overcoat,the coupling between neighboring interconnects on semiconductor devicesmay be reduced. As the lowest dielectric constant possible of a vacuum,materials with high degrees of free volume, such as materials of thepresent invention, may posses low dielectric constants, and may beuseful for reducing capacitive interactions between neighboringinterconnects. Accordingly, one embodiment of the invention involves alow-dielectric material comprising a shape-persistent molecule such asan iptycene. Any of the structures falling within iptycene-likestructures described herein can be used. In a preferred set ofembodiments dielectric materials of the invention comprisingshape-persistent molecules have a dielectric constant of less than 3.0,preferably less than 2.5, preferably less than 2.0, or preferably 1.5 orless. The invention includes electronic devices comprising dielectriccomponents comprising the shape-persistent molecules as would bewell-understood by those of ordinary skill in the art.

Additionally, molecules of the present invention may be fluorinated.Fluorinated molecules may display lower dielectric constants, and mayfurther reduce capacitive interactions between neighboring interconnectson semiconductor devices. Altering the hydrophobicity of the moleculesmay further reduce capacitive interactions.

Shape-persistent polymers may also have solubilizing side chains. Thesechains may be chosen, for example, to be hydrocarbons or perfluorogroups. Desirable materials may include those that do not contain polarfunctionality, and may be reoriented or polarized by electric fields,giving a low dielectric constant. Furthermore, the molecular structuresmay be are chosen such that the molecules have no affinity for water,such as atmospheric water.

Examples of iptycenes contemplated by the present invention areillustrated in FIGS. 2A, 2B, 2C, 2D and 2E. FIG. 2A shows examplelinkages by which an iptycene may be connected through at least any twopositions. X may be any chemical structure, for example, an alkyl, anaryl, an iptycene, or an inorganic. FIG. 2B illustrates a sampleiptycene that may be used as a dielectric polymer. FIG. 2C showsiptycenes used in a block or random co-polymer. X or Y may be aniptycene. FIG. 2D shows iptycenes as pendant groups on a polymer chain.The polymer may be, for example, a random, a block, or a graft polymer,and the homopolymer or each block of a block-polymer may be a tactic,isotactic, or syndiotactic. FIG. 2E shows several iptycene polymers thatmay be used as dielectric materials. “ROMP” stands for ring-openingmetathesis polymerization. The number of repeat units in molecules ofthe invention (n) typically is from about 5 to about 1,000, preferablyfrom about 10 to about 500, and more preferably from about 10 to about200. In FIG. 2E the measured dielectric constant of molecule 800 is2.63. The dielectric constant of molecule 801 is 2.67, and thedielectric constant of molecule of 802 is 2.72. In FIG. 2D, X and/or Ymay be iptycenes, optionally functionalized, and R can be essentiallyany chemical structure, for example, alkyl, aryl, etc. If X equals Y,then the polymer may be a tactic, isotactic, or syndiotactic. If X isnot identical to Y, then each block may be a tactic, isotactic, orsyndiotactic.

As an illustrative example, in a shape-persistent polymer comprised onlyfrom benzoid rings and hydrocarbon side chains, the reduction indielectric constant that will accompany the internal free volume can bedetermined as follows. For a material with 50% free volume, thedielectric constant may be reduced to about 1.55 (vacuum=1.0). For amaterial with 70% free volume, the dielectric constant may be about1.33, and for 90% free-volume dielectric constant may be about 1.09. Incontrast, conventional SiO₂ dielectrics with the proper performancetypically have dielectric constants of 3.5 to 4.0. Thus, a material witha composite of a shape-persistent materials and a polymer needed to meetother barrier and adhesive properties may be useful as a dielectriccoating in high performance integrated circuits.

In one embodiment, the materials of the present invention incorporatefree volume directly into the molecular design, allowing for greateruniformity of pore sizes, as well as smaller pore sizes. The presentinvention provides sub-nanoporous materials in accordance with one setof embodiments. “Sub-nanoporous” materials are defined herein asmaterials with pores smaller than 10 nm, preferably smaller than 5 nm,and more preferably smaller than 4 nm in size. The structures of thematerials may be rigid and non-collapsible. The small pore size maydecrease or eliminate metal diffusion and short-circuiting, or lower thedielectric constant of the material.

Polyiptycenes and other shape-persistent polymers disclosed here mayhave nanoscopic pockets of air, and may display high compressibility inparticular directions. Accordingly, another aspect of the inventioninvolves polymeric compositions of the invention constructed andarranged to absorb a compression-causing force. Such an arrangementwould be understood by those of ordinary skill in the art, and includesconstructions in essentially any known shock or force-absorbingstructure such as an athletic shoe sole, automobile bumper, or any othercushioning structure.

In one embodiment, the shape-persistent polymers of the invention may beused to bind polymer chains together. The polymers function as molecular“clips” for polymers, keeping them bundled together and preventing themfrom splaying. These methods may be used to produce materials with largematerial strengths. Bundling materials together may prevent singlechains from bearing a full load applied to a material.

In another embodiment, shape-persistent structures of the presentinvention may be used to bind molecules and polymers within theirinternal structures. The interaction of the shape-persistent structurewith other molecules is anisotropic, providing a preferred orientationbetween elements. This effect produces a new method for aligningmaterials in liquid crystals and polymers. Host materials, such asliquid crystals or polymers, may fill the free volume as defined by therigid shape-persistent guest. These structures may used in, for example,liquid crystals or polymer films.

The “aspect ratio” is defined as the ratio of the dimensions of thematerial. For alignment of a solute in a uniaxial polymer or liquidcrystal matrix, the relevant aspect ratio is the longest axis of thematerial divided by its next longest axis. Alternative aspect ratios maybe defined based on the specific nature of the solute.

An efficient packing may be accomplished by a “threading” mechanismwherein the liquid crystal packs within the iptycene void spaces, suchas depicted in structure 255 in FIG. 3. This observed solvation moleculemay fill the empty spaces created by the iptycenes while minimallydisrupting alignment of the host. In contrast, in structure 250 in FIG.3 the opposite aspect ratio alignment does not efficiently fill thevoids, and causes a greater disruption to the nematic phase. Bythreading molecules such as liquid crystal molecules through the voidspaces, the volume may be efficiently filled. Incorporated molecules,such as, for example, anthracene, may be aligned perpendicular to itsaspect ratio. This alignment may be governed by the minimization of freevolume of the system.

The three-dimensional structures of triptycenes result in specialsolvation properties that may create unique solute orientations. Thevoid spaces between aromatic triptycene faces allow threading of othersmall molecules, for example, liquid crystals, and macromolecules, forexample, polymers, through these spaces. This interaction causeschromophores that are part of the iptycene backbone to align. In somecases alignment may occur by application of a source of external energy,such as an electric, magnetic, optical, acoustic, electromagnetic, ormechanical field.

This alignment may be used, for example, in color liquid crystaldisplays. The organization of dichroic dyes in nematic liquid crystalsmay be required to make a color liquid crystal display. The contrast inthese displays may be determined by the contrast ratio between thedifferent states, resulting from the realignment of the liquid crystaldirector with an electric field. The liquid crystal director in anematic liquid crystal may be defined as the average direction overwhich a large grouping of molecular long axes of the liquid crystalpoint. Control of the director direction may be accomplished in displaysby surface forces and electric fields. The individual host molecules maybe disordered and have a distribution of directions about the director.The absolute value of the average angle that the individual moleculesdeviate from the director (direction of orientation) may be used tocalculate an order parameter. The size of this angle may be related tointermolecular interactions, thermal fluctuations, and the aspect ratioof the liquid crystals.

Conjugated polymers may be used to fabricate electronics devices.Applications in devices such as light emitting diodes, field-effecttransistors, photovoltaic devices, and sensors may be envisioned. In oneaspects of the invention, bulky properties of conjugated polymers may betailored using controlled organization of the polymer chains.

The uniform or quasi-uniform orientation of conjugated polymers may bethe result of in the increase of the conductivity and the emission ofpolarized light. Alignment of the molecules may be achieved usingself-organizing liquid crystalline polymers, Langmuir-Blodgett films, ormechanical stretching. Alignment may also be achieved by dissolving thematerial (“guest”) in a liquid crystal (“host”). The directedorientation of solute molecules in liquid crystals takes place as aresult of the anisotropic interactions between the two components, knownas the “guest-host effect.”

The solubility of conjugated polymers may be increased by attachingpendant groups such as alkoxy, alkyl, alkylsilyl, or phenyl groups tothe main chain. Incorporating iptycenes in poly(p-phenylene ethylene)s(“PPE”) or poly(p-phenylene vinylene)s (“PPV”) may minimize interpolymerchain contacts so as to increase the fluorescence efficiencies. PPVs maybe prepared through the coupling between aryl diiodides and phenylenebis(vinylboronate) derivatives, similar to the coupling of arylborateand aryl halide (the “Suzuki” reaction) used in the synthesis of biarylcompounds. Due to the general requirement of highly pure difunctionalmonomers in step growth polymerizations, pinacol ester derivatives ofbisvinyl borates were designated as monomers for the synthesis of PPVsto ensure efficient purification. Pinacol esters of organic borates arestable to column chromatography conditions, facilitating purification.Iptycene moieties may also be incorporated into other conjugated systemsto generate polymers with variety of electronic properties.1,4-diethynyltriptycenes may be prepared as a precursor for thesynthesis of both PPV- and PPE-containing triptycene moieties.

If such a structure is dispersed in a liquid crystal or a stretchedpolymer, the structure may align in such a way that its longest axislies perpendicular to the direction of orientation of the liquid crystalor the polymer. A composite material containing the shape-persistentpolymer and a polymer such as, for example, polyethylene, can exhibitwhat is known as a negative Poisson ratio (“NPR”). Materials with suchproperties are also called “auxetics.” An NPR or an NPR material refersto the situation wherein a material being stretched along one axis willexpand along another, contrary to what is typically exhibited bypolymers.

Accordingly, another aspect of the invention involves use of materialsand/or polymers of the invention in constructions making use of NPRs.NPR materials of the invention may be used as structural and mechanicalmaterials. NPR materials of the invention may also be used as adhesivesthat, when delamination is attempted, the polymer filling theinterstitial pores of an object expands and does not pull out of thestructure in which it is embedded. NPR materials may also be used in,for example, fasteners or nails that resist any attempt to remove themby pulling. Since the Poisson ratio of a material has an effect on thetransmission and reflection of internal stress waves, NPR materials ofthe invention define a new class of materials that more efficientlydistribute stress around holes and cracks. This may be especially usefulin, for example, sandwich paneling for aircraft and automobiles.Additionally, such sandwich paneling made from negative Poissonmaterials may adopt a much stronger convex shape upon bending ratherthan a saddle shape which positive Poisson material exhibit, and absorbimpact without being damaged. This effect may make it difficult for aprojectile or other object to puncture an object made from a negativePoisson material. Thus, NPR materials may also be used in the design ofprotective gear, such as, for example, bulletproof vests or shatterproofwindows. In one set of embodiments, NPR materials of the invention areformed by assembling a network of polymeric shape-persistent material,such as structure 240 of FIG. 2, which inherently includes very smallpores (e.g. those of about.3, 4, 5, 6, 7, or 8 Angstroms internaldiameter) A second polymer that threads the pores, when loosened, allowsthe overall structure to collapse upon itself to some degree. That is,structures 240 can be made to align relative to each other where commonmolecules that thread pores of a adjacent molecules 240 are nottensioned. Once such molecules threading the pores are tensioned,molecules 240 will be forced to orient parallel to each other creatingadditional free volume and increasing the overall volume of thestructure. Thus, a NPR material is defined.

The function and advantage of these and other embodiments of the presentinvention will be more fully understood from the examples below. Thefollowing examples are intended to illustrate the benefits of thepresent invention, but do not exemplify the full scope of the invention.

EXAMPLE 1

Triptycenes 25 and 26 in FIG. 4 have large free volumes between theiraromatic faces, aligned normal to the host alignment to efficiently fillthis volume. The orientation of triptycenes 25 and 26 may be quantifiedusing anthracenyl groups that have optical absorptions withwell-established polarizations. Triptycenes 25, and 26 havinganthracenyl groups were introduced into a room temperature nematicliquid crystal. Small aromatic guest molecules may align uniaxially innematic liquid crystalline solvents or stretched polymer sheets.Alignment may proceed such that the director axis of the nematic liquidcrystal or stretching direction of a polymer film is parallel to thelong-axis of the guest molecule. This effect may be visualized throughpolarized UV-Vis and IR spectroscopies. Polarized UV-Vis spectra oftriptycenes 25 and 26 were compared with anthracene 24, which alignsaccording to its aspect ratio and may thus be used as a probe ofmolecular orientation. The aspect ratio for each of the three moleculesis defined by the ratio of their longest to shortest axes and are 1.84for anthracene 24, 2.54 for triptycene 25, and 3.34 for triptycene 26.Based upon aspect ratio considerations, alignment of the long axis ofeach molecule with the host alignment direction increases across theseries from 24 to 26.

Homeotropic alignment of 1 wt % mixtures of anthracene 24 andtriptycenes 25 and 26 in 4-(trans-4-pentylcyclohexyl)benzonitrile wasachieved using surface rubbed test cells to give uniaxial alignment.Polarized spectra of anthracene 24 in the nematic liquid crystal wereconsistent with previous literature reports, showing alignment of themolecules with their long-axes along the nematic liquid crystaldirector. The transition moment of the lowest energyvibronically-coupled absorption (320-380 nm) of anthracene 24 wasshort-axis polarized, and therefore gave larger UV-Vis absorption withlight polarized perpendicular to the liquid crystal director.Observation of the polarization dependence of the similar absorptionbands of the anthracenyl-moieties of triptycenes 25 and 26 allowed fordetection of their orientation.

Upon measurement, the dichroic ratio of mixtures of triptycenes 25 and26 were found to be the inverse of anthracene 24, shown in FIG. 5; thedichroic ratio, A_(//)/A, for these molecules are listed in TABLE 2.A_(//)/A for triptycenes 25 and 26 was >1.0, while for A_(//)/A was <1.0for anthracene 24. Larger absorptions (320-380 nm) were seen whenexposed to parallel polarized light versus perpendicular. This was mosteasily seen in the 0-0 absorption at 380 nm that was purely short-axispolarized. The higher energy vibronically-coupled absorptions begin tooverlap a higher energy long-axis polarized transition.

The observed dependence implies that the alignment of the anthracenechromophores of the triptycenes was normal to the liquid crystaldirector, a result in which is opposite to the alignment expected onaspect ratio alone. This alignment was likely a result of the large freevolume of the iptycene molecules. Based on the aspect ratio argument,triptycene 26 would be expected to align the most efficiently since ittraces out larger void spaces due to its size; triptycene 25 would beexpected to align poorly. However, triptycene 25 also showed goodalignment. The smaller void spaces created by triptycene 25 weresufficient to align molecules showing the powerful effect of void spacescoupled with a rigid backbone.

As an elucidation of the “threading” model, thin solution-cast polyvinylchloride films containing 1 wt % anthracene 24 and triptycenes 25 and 26were prepared. These molecules were uniaxially stretched to impartmacromolecular alignment. The enlarged UV-Vis window of polyvinylchloride versus the liquid crystal allows observation of both the stronganthracene absorption at 250 nm as well as the weak 350 nm absorption.As with the liquid crystal host, anthracene 24 aligns with its long-axisalong the stretching direction, while triptycenes 25 and 26 both showeda preference for alignment of their long axes normal to the stretchingdirection, as illustrated in FIG. 6. This can be seen in bothabsorptions at 260 nm and 380 nm as an inverse relationship with respectto incident polarization. The alignment is reflected in the dichroicratios listed in TABLE 2. In all cases, the alignment provided byuniaxial polyvinyl chloride was lower than that achieved by liquidcrystal alignment.

EXAMPLE 2 Quinone-Containing Monomers

The preparation of ribbon-type polyiptycenes, illustrated in FIGS. 6Aand 6B, requires the synthesis of a triptycene containing both a dieneand dienophile within the same molecule. Polymerization occurs viaDiels-Alder condensation. A triptycene synthesized in this fashion wascompound 613 from the condensation of 1,4-dimethoxyanthracene 602 andcompound 609. To aid in polymer solubility in common organic solvents(chloroform, THF, dichloromethane, etc.), long alkyl-groups wereappended to monomer 613 via 609.

Starting with 1,2,4,5-tetrabromobenzene, compound 607 was prepared bytrapping the benzyne formed by addition of n-BuLi with 2,5-dioctylfuran.Then, TiCl₄/Zn deoxygenation of 607 yielded naphthalene 608 which wasconverted to the desired compound 609 via trapping of the benzyne formby addition on PhLi with furan. The reaction of 602 and 609 in decalinat 190° C. for 2 days, yielded the Diels-Alder adduct 610 which wasdehydrated to the anthracene 611 with polyphosphoric acid at 150° C.Finally, the quinone was obtained through demethylation with BBr₃ indichloromethane to obtain hydroquinone 612, then subsequent oxidation tothe quinone 613 with AgO in acetone.

Another route to these monomers is illustrated in FIG. 6C, wherereaction of 1,4-anthraquinone with an excess of 1,4-dimethoxyanthracenein refluxing acetic acid gave quinone 630. Addition of MeLi to bothketones, followed by TiCl₃/LiAlH₄ reduction of the resulting diol gaveanthracene derivative 631. Then, the same methylation and oxidationprocedure vide supra yields monomer 633, with methyl groups proximal tothe bridgehead.

EXAMPLE 3 Epoxy-Containing Monomers

To prepare epoxy-containing monomer 616, the previous synthetic schemewere slightly altered, as illustrated in FIG. 6D. Reaction of2,3-dibromo-1,4-dimethoxyanthracene 603, obtained by NBS bromination of1,4-dimethoxyanthracene 602 in DMF, with 609 for 3 days at 190° C. indecalin yielded adduct 614. Dehydration of 614 with polyphosphoric acidor trimethylsilyl polyphosphate gave anthracene 615. Final trapping ofthe benzyne, formed by PhLi addition to 615, with furan, gave monomer616. Compound 616 has two diastereomers (henceforth, fast-616 andslow-616) that are easily separated by column chromatography.

EXAMPLE 4 Hyperbranched Monomers

Multi-functional monomers may be required for forming hyperbranchedpolymers, as illustrated in FIG. 6E. Hyperbranching has the effect ofgreatly increasing the molecular weight of the polymer. Triptycenescontaining multiple dienes or dienophiles are used in this example.

For multiple dieneophiles, anti-1,4:5,8-diepoxyanthacene 621 may beused, but synthesized monomer 618 containing two octyloxy-groups forincreased solubility may also be used. The synthesis was started byadding alkyl groups to 2,3,5,6-tetrabromohydroquinone via a Williamsonether synthesis, giving compound 617. Then, trapping both benzynesformed from 617 with addition of PhLi in the presence of furan yieldedmonomer 618. Monomer 618 was produced in two diastereomers where bothepoxy-groups are either in a syn- or anti-arrangement (53%:47%syn:anti), and were easily separated by column chromatography.

For multiple dienes, monomer 620 was synthesized, giving threeanthracene moieties within one triptycene-like core. This was made by aFriedel-Crafts reaction of triptycene with phthalic anhydride in thepresence of AlCl₃. Then, ring closure of the tris-ketoacid withconcentrated sulfuric acid gave compound 619. Conversion of 619 to 620was achieved with Al/HgCl₂ in cyclohexanol.

EXAMPLE 5 Ring Opening Metathesis Polymerization (ROMP) Methods

Monomers for direct incorporation of iptycenes into the backbone of aprocessable polymer may require a reactive alkene for use inring-opening metathesis polymerization. Along these lines, bothdiastereomers of 616 may be used, however, the tetrahydrofuransubstructure in the resulting polymer would be less stable than thecorresponding cyclopentane structure. To provide a more stablestructure, monomer 623 was prepared, as illustrated in FIG. 6F.

Starting from monomer 613, Diels-Alder reaction of the quinone withfreshly prepared cyclopentadiene in acetonitrile at 0° C. gave adduct622. Subsequent tautomerization of the adduct with sodium hydride in DMFfollowed by methylation with dimethyl sulfate gave monomer 623.

Monomer 623 may be used as a co-monomer (1%-100%) with norbornene inROMP polymerizations to produce a co-polymer 624 with iptycenes directlyin the backbone. Hydrogenation of the remaining double bonds willproduce a processable polymer 625 with a potentially negative Poissonratio.

EXAMPLE 6 Polymerization Results

Heating solid samples of diastereomers of 616 (fast-616; slow-616) for1-4 hours to 200-250° C. under N₂ yielded polymers of various sizes andpolydispersities. By gel permeation chromatography (GPC), THF solublefractions gave the molecular weights and polydispersities listed inTABLE 1. Addition of hyperbranched monomers 620 and 621 allowed forinitial attempts at hyperbranched polyiptycenes. Mass spectroscopy mayalso be used to determine the extent and cleanliness of polymerization.

Hyperbranching allows for higher molecular weights with lower overallreaction yields. If all complementary groups are in equal numbers, 90%yields without hyperbranching gives an average degree of polymerizationof 10; while hyperbranched monomers, with an average number offunctional groups per monomer of 3, would give the same average degreeof polymerization at 60% yield. However, imbalance in reactive groupstends to decrease the average molecular weight due to all chains beingcapped by the same monomer. This effect can be seen in the decreasedmolecular weight of Entry 6 of TABLE 1 versus Entry 4. However,hyperbranching does cause decreased solubility of the polymer. Themaxima for most of the gaussians that describe each molecular weightdistribution for Entries 1-7 lie in the 10,000-20,000-g/mol range. Theseweights correspond to average degrees of polymerization of 14-28repeating units (based in 616). Ultimately, the fully aromaticpolyiptycenes will be prepared by dehydration of 651 the intermediatepolymers described above, via acid-catalyzed dehydration methods toyield 652.

EXAMPLE 7 Triptycenes in Liquid Crystalline Displays

In this example, the extended free-volume guided alignment of triptycenewas used to increase the alignment of commonly used dichroic dyes forliquid crystalline displays (LCDs). Dyes 0, 27, 28, 29 and 30, asillustrated in FIG. 7, were synthesized to study the effect offree-volume alignment of triptycenes on the alignment of dyes. Thesedyes were designed such that multiple triptycenes could be incorporatedand the triptycene free-volume is co-incident to the aspect ratio of thedye.

Dyes 0, 27, 28, 29 and 30 were dissolved in a common liquid crystal host(1 wt % in 4-trans-(4-pentylcyclohexyl)benzonitrile) and homogeneouslyaligned in a rubbed polyimide coated test cell (10 μm thick). PolarizedUV-Vis spectra, parallel and perpendicular to the liquid crystalalignment, were recorded and their observed order parameters calculatedaccording to the following equation:S _(ob)=(A _(//) −A _(perp))/(A _(//)+2A _(perp))These results are summarized in TABLE 3. The polarized UV-Vis spectrafor Dyes 0, 27, 28 and 29 are shown in FIG. 8, with all 90° polarizedspectra normalized to illustrate the trend in the data. A step-wise,nearly linear increase in the alignment parameters of each dye was seenin the series from Dyes 0 to 27 to 29. With increasing triptyceneincorporation in the dye, alignment increases from 8%, to 15%, andultimately to 27% with respect to Dye 0.

Dye 30 was designed under the assumption that pentiptycene would give agreater increase in alignment with respect to triptycene, due to itsgreater free-volume. However, dye 30 did not have increased alignment,but rather decreased with respect to dye 27. This can be attributed tothe restricted environment around the central ring of the pentiptycenemoiety. Only one liquid crystal molecule can occupy either face of thepentiptycene, where the U-shaped cavity prevents facile rotation,decreasing the local entropy. Triptycenes, on the other hand, allow formore rotational and positional entropy in the nematic liquid crystal.These can sense the director of the liquid crystal and act as astabilizer-wing to average out the local motions of the host liquidcrystal.

To further demonstrate the generality of the effect of the triptyceneson more complex dyes, Dyes 31 and 32 in FIG. 7 were synthesized.Aminoanthraquinone dyes are popular for use in LCDs due to their vividcolors, high extinction coefficients, and longevity. Dyes 31 and 32 weresynthesized to determine if triptycenes gave the same alignmentenhancement in these dyes, as in the bis(phenylethynyl)benzene cases.The 1,5-diaminoanthraquinone forms have greater flexibility androtational freedom and their transition dipole slightly off the longaxis of the anthraquinone.

As in the previous case, the triptycenes were attached to the dyebackbone such that their free-volume guided alignment was complimentaryto the aspect-ratio guided alignment of the dye. This design increasedin the order parameter with respect to dye 31 on the order of 9%. Thepolarized UV-Vis spectra for dyes 31 and 32 are shown in FIG. 9.

EXAMPLE 8

As previously stated, increasing the aspect ratio of a dye may increasethe order parameter of dichroic dyes. This is most often achieved byattachment of longer alkyl groups, or extending the size of thechromophore. By extending the dye design into an additional dimension,the size of the molecule is maintained. The overall length of thetriptycene-containing dye molecules remains the same while the alignmentis increased. This provides dyes with greater solubility withoutsacrificing alignment. This may be a very powerful tool for designingdichroic dyes with higher alignments for a variety of applications fromguest-host reflective LCDs to holographic data storage. The synthesis ofdyes 27-29, and 32-38 (dichroic and fluorescent), showing greateralignment, were synthesized and prepared as illustrated in FIGS. 9A, 9B,9C, and 9D.

It is also possible for the dye itself, wither dichroic or fluorescentto be a liquid crystal. In particular, upon cooling from an isotropicstate (I), compound 27 enters a nematic liquid crystalline phase (N) at148° C. and crystallizes (C) at 123° C.

The nematic phase exhibited by 27 may afford the opportunity to makevery concentrated solutions of dyes in other nematic liquid crystalsused in display or non-linear optical applications since nematic liquidcrystals are known to be continuously miscible in varying concentrationsin other nematic liquid crystals. It may also be possible to make 27and/or analogs to display a biaxial optical properties in the nematicphase (biaxial nematic liquid crystal).

EXAMPLE 9

The synthesis of triptycene bis(vinyl-dioxoborolane) 43 is shown FIG.9E. 9,10-Dihydro-9,10[1′,2′]-benzenoanthracene-1,4-diol 39 was preparedfrom commercially available anthracene and 1,4-benzoquinone followingthe procedure of Bartlett et al., Journal of the American ChemicalSociety, 64:2649 (1942). Aryl nonafluorobutanesulfonates (nonaflates)are known to react readily with organozinc reagents in the presence ofpalladium catalysts and have a slightly higher reactivity compared tothe corresponding aryl triflates. To activate the hydroxy groups in 39for cross coupling, the hydroquinone derivative was treated withcommercially available CF₃(CF₂)₃SO₂F in the presence of triethylamine at25° C. The conversion was complete within 12 hours and the product wasobtained in high yield (98%). The palladium-catalyzed cross-couplingreaction of bisnonaflate 40 with trimethylsilylethyne in the presence ofCuI and triphenylphosphine in diisopropylamine furnished thebis(trimethylsilylethynyl) triptycene 41 in 86% yield. Treatment oftriptycene 41 with a solution of KOH in methanol in THF afforded thediethynyltriptycenes 42 in 90% yield. This triptycene with two ethynylgroups at the 1,4 positions could then be used as a monomer for thesynthesis of poly(p-phenylene ethynylene)s through coupling witharyldiiodides. Heating compound 42 with4,4,5,5-tetramethyl-1,3,2-dioxoborolane in dry toluene afforded thebis(pinacolvinylborate) 43, which was purified by chromatography.

In a similar manner, triptycene monomers 48 and 49 carrying twotert-butyl groups were prepared, as illustrated in FIG. 9F. Thetert-butyl groups in the monomers were expected to further limit theinteraction between polymer chains. 2,6-di-tert-butyl-anthracene 44 wasprepared from anthracene through a Friedel-Crafts reaction. Diels-Alderreaction of 44 with 1,4-benzoquinone and isomerization of the resultingadduct resulted in triptycene hydroquinone 45. Activation of 45 into thecorresponding bisnonaflate 46 followed by a Sonogashira coupling with3-hydroxy-3-methyl-but-1-yne afforded thebis(3-hydroxy-3-methyl-but-1-ynyl) fuctionalized triptycene 47.Treatment of 47 with KOH in toluene at 120° C. for 1.5 hours furnishedthe diacetylene 48. Hydroboration of 48 furnishedbis(vinyl-dioxaboborolane) 49, which was purified by flashchromatography.

Two aryldiiodides 50 and 51, prepared following the procedure of Swageret al., Journal of physical Chemistry, 99:4886-4893 (1995).Aryldiiodides 50 and 51 were coupled with the bis(vinyldioxaborolane)s.The coupling of the diiodides with 43 and 49 in the presence of a baseor fluoride afforded the triptycene incorporating PPVs 52, 53, 54 and55, as illustrated in FIG. 9G. A variety of conditions were screened tooptimize the polymerization by varying the solvent, catalyst, base, andreaction temperature. Best reproducible results were obtained bycarrying out the polymerization in dry NMP in presence of CsF andPd(PPh₃)₄. All the resulting PPV's were highly soluble in common organicsolvents. Polymer molecular weights were found to be around 12 kDacorresponding to about 15 to 20 repeating units as determined by GPC.Absorption, emission spectra state were recorded in both solution andsolid. The absorption and emission spectra alkyl substituted PPVs 54 and55 were shifted to the blue region relative to the alkoxy substitutedpolymers 52 and 53. The absorption spectra recorded on thin films werequite similar to those recorded on solutions, indicating negligibleinterchain interactions in the ground state. Fluorescence spectra of thethin films showed slight red shift relative to those of solution andposses similar shape, indication minimized excimer formation.

FIG. 9H shows the synthesis of a tripycene containing oligo(phenylenevinylene) and an oligo(phenylene ethynylene) with donor-acceptor groupson each end. Phenyelene vinylene 59 was obtained by coupling4-(dihecylamino)-iodobenzene and 4-bromobenzonitrile withbis(vinyldioxaborolane) 43. The phenyelene ethynylene 60 was obtained bycoupling 4-(dihecylamino)-iodobenzene and 4-bromobenzomitrile with thediacetylene 42. Both materials are highly soluble in liquid crystals andhighly fluorescent with compound 59 fluorescing orange while compound 60fluoresces green.

EXAMPLE 10

PPEs 56 and 57 in FIG. 9G with triptycenes in the backbone wassynthesized by the coupling reactions of molecules 42 and 48,respectively, with diiodide 51 in a mixture of toluene anddiisopropylamine in the presence of Pd(PPh₃)₄. Polymers with highermolecular weights (M_(n)=50 kDa) could be obtained. By polymerizing themonomers in the presence of small amount of phenylacetylene 58 (2-10 mol%), lower molecular weight PPE's were also obtained comparable to thoseof the PPVs. Absorption, emission spectra of the PPEs all shifted to theblue site of the corresponding PPVs and the iptycene polymers withalkoxy substitutions on the main chain. Those PPEs with molecularweights (i. e., M_(n)<25 kDa) could be solubilized in the liquidcrystals and could be aligned as determined of absorption spectrathrough a polarizer. The ordering parameter of the PPEs in the liquidcrystals were found to be slightly higher that of the correspondingPPVs. As an example, the absorption spectra of polymer 57 are also shownin FIG. 10. The absorption spectrum in LC was more red-shifted than thatof the thin film relative that of the solution. This indicates a moreplanar polymer conformation as a result of the interaction between thepolymers and the liquid crystals. The absorption parallel to thepolyimide director decreased as the temperature increased across thetransition temperature of the liquid crystal, as a result of loss ofdirectional order.

Fluorescence spectra of a liquid crystal solution of polymer 57 in a LCcell are shown in FIG. 11. The emission in the liquid crystal isslightly red-shifted but the shape of the spectrum is more solution-likeindicating no significant excimer formation. The fluorescence could alsobe switched by the application of electric field.

PPVs with triptycene in the main chain were prepared through aSuzuki-type coupling procedure. These polymers were highly soluble andcover a wide range of absorption and emission spectra. PPEs withtriptycene in the main chain and alkyl pending groups were prepared bySonogashira coupling. PPVs have absorption and emission spectra in thelonger-wavelength regions than those of the corresponding PPEs. Alkylsubstituted conjugated polymers absorb and emit in the bluer region thanthe corresponding alkoxy substituted polymers. tert-Butyl groups on thetriptycenes increase the solubility of the polymers, have but littleeffects on the spectroscopic properties. Lower-molecular-weight PPEs andPPVs incorporating triptycenes form homogeneous solutions in liquidcrystals and align to high order. This indicates that these polymers areuseful materials for the fabrication of anisotropic optical films. Thealignment direction of the polymers in liquid crystals can be switchedby the application of electric field.

EXAMPLE 11 Synthesis of9,10-o-benzeno-9,10-dihydro-4-hydroxy-1-octyloxyanthracene

9,10-o-benzeno-9,10-dihydro-4-hydroxy-1-octyloxyanthracene 900 isillustrated in FIG. 9A. 17.3 g (125 mmol) K₂CO₃ was added to a solutionof triptycene hydroquinone (35.8 g, 125 mmol) in 500 ml DMF under Ar. 25ml (125 mmol) 1-bromooctane was then added dropwise over 1.5 h. Thesolution was heated to 50° C. for 24 h. The solution was then cooled toroom temperature and quenched by pouring into dilute aqueous NH₄Cl. Theproduct was extracted with Et₂O. The combined organic layers were washedwith dilute aqueous NH₄Cl and saturated aqueous NaCl. The organic layerwas then dried over MgSO₄ and filtered, and the solvent removed in vacuoto yield a mixture of mono- and dialkylated triptycenes. The solid wasadded to 1 M NaOH in a 50/50 mixture of EtOH and water. The resultingdark solution was filtered and rinsed on the filter with additional 1 MNaOH to yield a white powder (dialkylated product, 27.7 g, 43%). Thefiltrate was acidified with 5% HCl to precipitate the monoalkylatedproduct as a tan powder. The powder was filtered and dried to yield 25.4g (51%) of compound 900.

EXAMPLE 12 Synthesis of9,10-o-benzeno-9,10-dihydro-4-nofylyl-1-octyloxyanthracene

9,10-o-benzeno-9,10-dihydro-4-nofylyl-1-octyloxyanthracene 901 isillustrated in FIG. 9A. In a flame-dried Schlenk was added 125 mg (mmol)NaH under a N₂ atmosphere in a dry box and sealed with a septa. Theflask was removed, placed on a vacuum line, 10 ml DMF added, and cooledto −10° C. on a MeOH/ice mixture. Then, 1.20 g (3 mmol) of compound 900was added under positive Ar pressure and stirred at −10° C. for 1 hour.Cooling was then removed and the solution was allowed to warm to roomtemperature over 30 minutes. The solution was cooled back to −10° C. and0.625 ml (1.05 g, 3.45 mmol) n-perfluorobutanesulfonyl fluoride wasadded dropwise. The solution was stirred at −10° C. for 1 hour, thenallowed to stir at room temperature for 2.5 hours. The solution wasquenched by pouring into saturated aqueous NH₄Cl. The product wasextracted with Et₂O and the organic layers combined. The organic layerwas washed with saturated aqueous NH₄Cl, water, and saturated aqueousNaCl. After drying over MgSO₄ and filtering, the solvent was removed invacuo to yield a tan-orange oily solid. The solid was titrated with 95%MeOH to yield a tan solid which was filtered and dried to yield 1.75 g(86%) of compound 901.

EXAMPLE 13 Synthesis of9,10-o-benzeno-4-ethynyl-9,10-dihydro-1-octyloxyanthracene

9,10-o-benzeno-4-ethynyl-9,10-dihydro-1-octyloxyanthracene 902 isillustrated in FIG. 9A. 680 mg of compound 901 (1 mmol), 70 mgPdCl₂(PPh₃)₂ (0.1 mmol), and 40 mg CuI (0.2 mmol) were placed into aSchlenk tube. The tube was backfilled with Ar. 5 ml diisopropylaminefollowed by 0.3 ml trimethylsilylacetylene was then added to the tube.The tube was sealed with a Teflon stopper and heated to 90° C. for 20hours. After cooling, the solution was filtered through a plug of silicagel twice, the first time with CHCl₃. The first filtrate was condensedin vacuo, dissolved in hexanes and flushed through a plug of silica asecond time with 4:1 hexanes:CHCl₃. Removal of the solvent in vacuoyielded an orange oil which was used without further purification.

The orange oil was dissolved in 8 ml THF. 8 ml MeOH is added and thesolution purged with Ar for 30 minutes. Next, 555 mg K₂CO₃ was added andthe solution stirred at room temperature for 3 hours. The solution wasquenched by pouring it into water and extracting with Et₂O. The combinedorganic extracts were washed with saturated aqueous NH₄Cl, water, andsaturated aqueous NaCl. After drying over MgSO₄, the solution wasfiltered and condensed in vacuo to yield an orange oil. Purification ofcompound 902 was by gradient column chromatography from 6:1 to 3:1hexanes:CHCl₃ to yield 342 mg (81%) of a pale yellow oil whichsolidifies upon drying under vacuum.

EXAMPLE 14 Synthesis of1,4-bis(4′-octyloxyphenylethynyl)-9,10-o-benzeno-9,10-dihydroanthracene

1,4-bis(4′-octyloxyphenylethynyl)-9,10-o-benzeno-9,10-dihydroanthracene27 is illustrated in FIG. 9A. In a Schlenk tube was placed 1.012 g1,4-diiodotriptycene and 1.072 g 1-ethynyl-4-octyloxybenzene. The tubewas purged with Ar. Then, 20 ml toluene and 10 ml diisopropylamine wereadded and the solution purged for 30 minutes, after which 60 mgPdCl₂(PPh₃)₂ and 30 mg CuI were added. The solution became dark incolor. The solution was sealed and stirred at room temperature for 48hours. The reaction was then filtered through a plug of silica gel toremove the catalyst and the silica was washed with dichloromethane.Removal of the solvent in vacuo yielded a dark solid. Purification wasby gradient column chromatography on silica gel with 3:1 to 2:1 to 3:2hexanes:chloroform. Removal of the solvent in vacuo yielded a paleyellow solid which was recrystallized from hexanes to yield 760 mg (54%)of compound 27 as white needles.

EXAMPLE 15 Synthesis of1,4-bis(9′,10′-o-benzeno-4′-ethynyl-9′,10′dihydro-1′-octyloxyanthracenyl)benzene

1,4-bis(9′,10′-o-benzeno-4′-ethynyl-9′,10′dihydro-1′-octyloxyanthracenyl)benzene28 is illustrated in FIG. 9A. In a Schlenk tube were placed1,4-diiodobenzene (41 mg, 0.125 mmol), Compound 902 (101 mg, 0.25 mmol),PdCl₂(PPh₃)₂ (5 mg), and CuI (2 mg). The tube was placed under Ar. Tothe tube was added 1 ml DIPA and 2 ml toluene. The tube was sealed andthe mixture stirred at room temperature for 15 hours. The solution wasfiltered through a plug of silica gel to remove the catalysts, and theplug was washed with chloroform. Removal of solvent in vacuo yielded ayellow solid. The solid was dissolved in a minimal volume ofdichloromethane. Compound 28 (60 mg, 54%) was then precipitated byaddition of MeOH. Analytically pure compound 28 as a white powder wasobtained by recrystallization from dichloromethane.

EXAMPLE 16 Synthesis of1,4-bis(9′,10′-o-benzeno-4′-ethynyl-9′,10′dihydro-1′-octyloxyanthracenyl)-9,10-o-benzeno-9,10-dihydroanthracene

1,4-bis(9′,10′-o-benzeno-4′-ethynyl-9′,10′dihydro-1′-octyloxyanthracenyl)-9,10-o-benzeno-9,10-dihydroanthracene29 is illustrated in FIG. 9A. In a Schlenk tube were placed1,4-diiodotriptycene (50 mg, 0.1 mmol), compound 633 (84 mg, 0.2 mmol),PdCl₂(PPh₃)₂ (4 mg), and CuI (2 mg). The tube was placed under Ar. Tothe tube was added 1 ml DIPA and 1.5 ml toluene. The tube was sealed andthe mixture stirred at room temperature for 17 hours. The solution wasfiltered through a plug of silica gel to remove the catalysts, and theplug was washed with chloroform. Removal of solvent in vacuo yielded ayellow solid. The solid was dissolved in a minimal volumedichloromethane. Compound 29 (93 mg, 88%) was then precipitated byaddition of MeOH. Analytically pure compound 29 as a white powder wasobtained by recrystallization from benzene.

EXAMPLE 17 5,7,12,14-bis(o-benzeno)-5,7,12,14-tetrahydro-6,13-bis(4′-octyloxyphenylethynyl)pentacene

5,7,12,14-bis(o-benzeno)-5,7,12,14-tetrahydro-6,13-bis(4′-octyloxyphenylethynyl)pentacene30 is illustrated in FIG. 9A. To a solution of 4-octyloxyiodobenzene(365 mg, 1.1 mmol), PdCl₂(PPh₃)₂ (20 mg), and CuI (10 mg) in 5 ml THFunder Ar, 6,13-bis(ethynyl)pentiptycene (239 mg, 0.5 mmol) was added.DIPA (1 ml) was then added and the solution heated to 50° C. for 5hours. After cooling, the reaction product was filtered through a plugof silica gel to remove the catalyst, and the plug was washed withchloroform. After removing the solvent in vacuo, the resulting solid wasrecrystallized from THF/MeOH to yield compound 30 (285 mg, 64%) as awhite powder.

EXAMPLE 18 Synthesis of Compound 903

Compound 903 is illustrated in FIG. 9B. p-benzoquinone (5.875 g, 25mmol) and 1-acetamidoanthracene (3.25 g, 30 mmol) were suspended in 125ml xylenes and heated to reflux for 20 hours. After cooling, theprecipitated solid was collected by filtration. This solid wasrecrystallized from xylenes and dried under vacuum to yield compound 903(4.87 g, 57%) as a tan solid.

EXAMPLE 19 Synthesis of Compound 904

Compound 904 is illustrated in FIG. 9B. In a Schlenk tube were placedcompound 903 (3.43 g, 10 mmol), 1-bromooctane (7.0 ml, 40 mmol), and KI(1.33 g, 8 mmol). 40 ml DMF was then added and the tube purged with Ar.K₂CO₃ (5.5 g, 40 mmol) was then added to the tube. The tube was sealedand heated to 80° C. for 2 days. After cooling, the solution wasquenched by pouring it into dilute aqueous NH₄Cl, and the solutionextracted with Et₂O. The combined organic extracts were washed withdilute aqueous NH₄Cl, H₂O, and saturated aqueous NaCl. The layer wasdried over MgSO₄ and filtered, and the solvent removed in vacuo to yielda brown solid. The solid was the recrystallized from MeOH to yieldcompound 904 (2.40 g, 43%).

EXAMPLE 20 Synthesis of Compound 905

Compound 905 is illustrated in FIG. 9B. Compound 904 (2.13 g) and NaOH(7.5 g) were suspended in MeOH (40 ml) and heated to reflux. Thereaction monitored by TLC (EtOAc:hexanes 1:1) until compound 905 wasconsumed. The reaction was cooled, poured into water, and extracted withEt₂O. The combined organic extracts were washed with water and saturatedaqueous NaCl. The layer was dried over MgSO₄ and filtered, and thesolvent removed in vacuo to yield a pale tan solid. The solid was thendissolved in acetone and acidified to pH 1 with 5% aqueous HCl toprecipitate compound 905 (1.89 g, 90%) as an off-white solid, whichfiltered and dried in vacuo.

EXAMPLE 21 Synthesis of Compound 32

Compound 32 is illustrated in FIG. 9B. Compound 905 (568 mg, 1 mmol),Cs₂CO₃ (285 mg, 3.5 mmol), Cu (2 mg), and 1,5-dichloroanthraquinone (70mg, 0.25 mmol) were combined in 1 ml DMF and heated to reflux for 24hours. After cooling, the solution was quenched by pouring it intodilute aqueous NH₄Cl, and the solution extracted with Et₂O. The combinedorganic extracts were washed with dilute aqueous NH₄Cl, H₂O, andsaturated aqueous NaCl. The layer was dried over MgSO₄ and filtered, andthe solvent removed in vacuo, yielding a red solid. Purification was bycolumn chromatography on silica gel with dichloromethane, removing thefirst bright red spot. Removal of the solvent in vacuo yielded a deepred solid. The solid was dissolved in a minimum volume THF and compound32 (56 mg, 18%) was precipitated by addition of MeOH.

EXAMPLE 22 Synthesis of Compound 33

Compound 33 is illustrated in FIG. 9C. In a Schlenk tube under Ar werecombined compound 902 (210 mg, 0.5 mmol), p-benzoquinone (48 mg, 0.45mmol), CuI (20 mg, 0.01 mmol), PdCl₂(PPh₃)₂ (2 mg, 0.002 mmol), toluene(2.5 ml), and DIPA (0.1 ml), adding DIPA last. The solution was stirredat room temperature for 8 hours, and the reaction quenched by theaddition of MeOH. The solution was then filtered through a plug ofsilica gel, and the plug washed with chloroform. After removal of thesolvent in vacuo, purification was by column chromatography on silicagel with 2:1 hexanes:dichloromethane. Removal of the solvent thenyielded compound 33 (131 mg, 63%) as a white solid. Analytically purecompound was obtained by recrystallization from benzene.

EXAMPLE 23 Synthesis of Compound 906

Compound 906 is illustrated in FIG. 9C. Into a flame-dried Schlenk tubewas placed 5,14-(o-benzeno)pentacene (71 mg, 0.2 mmol), dissolved in 1ml DMF. To this was added NBS (71 mg, 0.4 mmol) and the solution stirredat room temperature for 2 hours. The tube was wrapped with foil toexclude light. The reaction was then quenched by pouring into water toprecipitate compound 906 (98 mg, 96%), which was isolated by filtrationand dried in vacuo.

EXAMPLE 24 Synthesis of Compound 34

Compound 34 is illustrated in FIG. 9C. In a Schlenk tube under Ar wasplaced compound 906 (51 mg, 0.1 mmol) and 1-ethynyl-4-octyloxybenzene(58 mg, 0.2 mmol). Then, 1 ml toluene and 0.5 ml diisopropylamine wereadded, followed by 7 mg PdCl₂(PPh₃)₂ and 2 mg CuI. The solution wassealed and stirred at room temperature for 20 hours. The solution wasthen poured into water and extracted with dichloromethane. The combinedorganic extracts were washed with water, dilute aqueous NH₄Cl, andsaturated aqueous NaCl. After drying over MgSO₄ and filtration, removalof the solvent in vacuo yielded a dark solid. Purification of the solidwas by flushing through a plug of silica gel with chloroform. Removal ofthe solvent in vacuo yielded a solid, which was then dissolved in aminimal volume of chloroform. Compound 34 (35 mg, 43%) was thenprecipitated by the addition of MeOH, yielding an orange powder.

EXAMPLE 25 Synthesis of Compound 35

Compound 35 is illustrated in FIG. 9C. In a Schlenk tube under Ar wereplaced compound 902 (81 mg, 0.2 mmol) and4-bromo-N-butyl-1,8-naphthylimide (66 mg, 0.2 mmol). 1.5 ml toluene and0.5 ml diisopropylamine were then added, followed by 14 mg PdCl₂(PPh₃)₂and 4 mg CuI. The solution was sealed and stirred at room temperaturefor 20 hours. The solution was poured into water and extracted withEt₂O. The combined organic extracts were washed with water, diluteaqueous NH₄Cl, and saturated aqueous NaCl. After drying over MgSO₄ andfiltration, removal of the solvent in vacuo yielded a yellow-orangesolid, which was purified by flushing it through a plug of silica gelwith dichloromethane. Removal of the solvent in vacuo yielded a solidthat was titrated with hexanes to give compound 35 (93 mg, 71%) as ayellow powder.

EXAMPLE 26 Synthesis of 1,4-dinitrosotriptycene

1,4-dinitrosotriptycene 907 is illustrated in FIG. 9D. To a solution of1,4-triptycene dioxime (770 mg, 2.5 mmol) in 100 ml MeCN was dropwiseadded a solution of ceric ammonium nitrate (2.74 g, 5 mmol) in 10 mlwater. The solution was stirred at room temperature. Within one minute aprecipitate began to form. After 30 minutes, water was added. Compound907 (610 mg, 80%) was then isolated by filtration as a bright yellowsolid, and dried in vacuo.

EXAMPLE 27 Synthesis of Compound 36

Compound 36 is illustrated in FIG. 9D. To a solution of4-octyloxyaniline (500 mg) in iPrOH (5 ml) and AcOH (1 ml) was added1,4-dinitrosotriptycene (310 mg). The solution was heated to reflux for20 hours. The solution was poured into water and extracted withchloroform. The combined organic extracts were washed with water andsaturated aqueous NaCl. After drying over MgSO₄ and filtration, removalof the solvent in vacuo yielded an orange solid, which was purified byflushing through a plug of silica gel with dichloromethane. After theremoval of solvent in vacuo, analytically pure compound 36 was obtainedby recrystallization two times from EtOAc (254 mg, 35%).

EXAMPLE 28 Synthesis of Compound 37

Compound 37 is illustrated in FIG. 9D. To a solution of compound 905(free-based by shaking EtOAc solution with an aqueous NaHCO₃ solution)(580 mg, 1.1 mmol) in iPrOH (5 ml) and AcOH (1.25 ml) was added1,4-dinitrosobenzene (70 mg, 0.5 mmol). The solution was heated toreflux for 20 hours. The solution was then poured into water andextracted with chloroform. The combined organic extracts were washedwith water and saturated aqueous NaCl. After drying over MgSO₄ andfiltration, removal of the solvent in vacuo yielded an orange solidwhich adsorbed onto silica gel. Column chromatography on silica gel with3:2 hexanes:dichloromethane yielded compound 37 as the first major spoteluted. After the removal of solvent in vacuo, analytically purecompound 37 was obtained by recrystallization from EtOAc (156 mg, 27%).

EXAMPLE 29 Synthesis of Compound 38

Compound 38 is illustrated in FIG. 9D. A solution of naphthazarinintermediate (52.5 mg, 0.5 mmol) and 2-aminotriptycene (0.6 mmol) inAcOH (2 ml) was heated to reflux for 6 hours. The solution was thencooled and quenched in 5% aqueous HCl. Next, the product was extractedwith chloroform. The combined organic extracts were washed with waterand saturated aqueous NaCl. After drying over MgSO₄ and filtration,removal of the solvent in vacuo yielded a blue-green solid. Columnchromatography on silica gel with 5:1 dichloromethane:EtOAc yieldedcompound 38 (37 mg, 22%) as the first major spot eluted.

EXAMPLE 30 Synthesis of1,4-nonafluorobutanesulfonoxy-9,10-dihydro-9,10-[1′,2′]benzenoanthracene

1,4-nonafluorobutanesulfonoxy-9,10-dihydro-9,10-[1′,2′]benzenoanthracene40 is illustrated in FIG. 9E.9,10-Dihydro-9,10[1′,2′]-benzenoanthracene-1,4-diol 39 (21.0 g, 0.0733mol) was dissolved in dichloromethane (500 ml) and triethylamine (50ml). To this solution was added perfluobutanesulfonyl fluoride (52.0 g,0.172 mol). The reaction was stirred at room temperature for 20 h, andsilica gel (50 g) was added in small portions. The reaction was stirredat room temperature for 20 min and filtered through a short plug ofsilica gel column, which was rinsed with dichloromethane. The solventwas removed in vacuo, and the residue was dissolved in dichloromethane.Methanol was then added, and white crystals were collected by filtrationto give compound 40.

EXAMPLE 31 Synthesis of1,4-bis(trimethysilylethynyl)-9,10-dihydro-9,10-[1′,2′]benzenoanthracene

1,4-bis(trimethysilylethynyl)-9,10-dihydro-9,10-[1′,2′]benzenoanthracene41 is illustrated in FIG. 9E.1,4-nonafluorobutanesulfonoxy-9,10-dihydro-9,10-[1′,2′]benzenoanthracene40 (9.0 g, 10.58 mmol) was suspended in diisopropyamine (60 ml). Theflask was degassed and backfilled with argon. To the flask was addedpalladium bisdibenzylideneacetone (122 mg), triphenylphosphine (245 mg,0.93 mol) and copper iodide (41 mg, 0.22 mol), and the reaction wasfurther degassed and twice backfilled with argon. Under a flow of argon,trimethylsilylethyne (6.9 ml) was added and the flask was sealed andheated to 90° C. for 44 h. Solvent was removed in vacuo and the crudeproduct was purified by flash chromatography eluting with 6%dichloromethane in hexanes to give product 41 (4.07 g, 86%).

EXAMPLE 32 Synthesis of1,4-diethynyl-9,10-dihydro-9,10-[1′,2′]benzeno-anthracene

1,4-diethynyl-9,10-dihydro-9,10-[1′,2′]benzeno-anthracene 42 isillustrated in FIG. 9E.1,4-bis(trimethysilyethynyl)-9,10-dihydro-9,10-[1′,2′]benzenoanthracene41 (4.88 g, 10.92 mmol) was dissolved in THF (50 ml). A solution of KOH(2.8 g, 42.5 mmol) in methanol (10 ml) was added. The reaction wasstirred at room temperature for 30 min and the solvent was removed invacuo. The residue was purified by flash chromatography to give product42 (3.26 g, 99%).

EXAMPLE 33 Synthesis of1,4-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl-ethenyl)-9,10-dihydro-9,10-[1′,2′]benzeno-anthracene

1,4-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl-ethenyl)-9,10-dihydro-9,10-[1′,2′]benzeno-anthracene43 is illustrated in FIG. 9E.1,4-diethynyl-9,10-dihydro-9,10-[1′,2′]benzeno-anthracene 42 (410 mg,1.36 mmol) and 4,4,5,5-tetramethyl-1,3,2-dioxoborolane (0.60 ml, 0.53 g,4.14 mmol) was dissolved in dry toluene (1 ml). The reaction was heatedto 90° C. for 20 h and the solvent was removed in vacuo. Flashchromatography eluting with dichloromethane gave product 43 (400.2 mg,53%).

EXAMPLE 34 Synthesis of6,14-di-tert-butyl-9,10-dihydro-9,10[1′,2′]benzenoanthracene-1,4-diol

6,14-di-tert-butyl-9,10-dihydro-9,10[1′,2′]benzenoanthracene-1,4-diol 45is illustrated in FIG. 9F. 2,6-di-tert-butyl-anthracene (19.0 g, 0.0654mol) and 1,4-benzoquinone (7.78 g, 0.072 mol) in xylenes (150 ml) washeated to reflux for 2 h. Solvent was removed in vacuo and the crudeproduct was purified by flash chromatography (2:3,hexane:dichloromethane) to give benzenoanthracene-1,4-dione, which wasdissolved in acetic acid (150 ml) and heated to reflux and a drop ofaqueous HBr (48%). After 10 min, the reaction was cooled and water wasadded. Precipitates were collected and dried to give compound 45 as anoff-white solid (12.73 g, 0.0319 mol, 49%).

EXAMPLE 35 Synthesis of6,14-di-tert-butyl-1,4-nonafluorobutanesulfonoxy-[1′,2′]benzenoanthracene

6,14-di-tert-butyl-1,4-nonafluorobutanesulfonoxy-[1′,2′]benzenoanthracene46 is illustrated in FIG. 9F.6,14-di-tert-butyl-9,10-dihydro-9,10[1′,2′]benzenoanthracene-1,4-diol 45(4.52 g, 0.0113 mol) was dissolved in dichloromethane (50 ml) andtriethylamine (10 ml). To this solution was addedperfluo-1-butanesulfonyl fluoride (7.0 g, 0.0232 mol). The reaction wasstirred at room temperature for 20 hours, and silica gel (3 g) wasadded. The reaction was stirred at room temperature for 20 minutes andfiltered through a short silica gel column, eluted with dichloromethane.The solvent was removed in vacuo and the residue was purified by flashchromatography to afford compound 46 (9.85 g, 90%).

EXAMPLE 36 Synthesis of6,14-di-tert-butyl-1,4-bis(3-hydroxy-3-methyl-but-1-ynyl)-[1′,2′]benzenoanthracene

6,14-di-tert-butyl-1,4-bis(3-hydroxy-3-methyl-but-1-ynyl)-[1′,2′]benzenoanthracene47 is illustrated in FIG. 9F.6,14-di-tert-butyl-1,4-nonafluorobutanesulfonoxy-[1′,2′]benzenoanthracene46 (6.0 g, 6.24 mmol) was suspended in diisopropylamine (30 ml). Theflask was degassed and back-filled with argon. To the flask was addedpalladium bisdibenzylideneacetone (71.7 mg, 0.125 mmol),triphenylphosphine (143 mg, 0.545 mmol), copper iodide (34 mg, 0.179mmol), and 2-methyl-3-butyn-2-ol (1.33 g, 0.0158 mol). The reactionflask was further degassed and backfilled with argon twice, sealed andheated to 90° C. for 60 h. The solvent was removed in vacuo and thecrude product was purified by flash chromatography eluting with 8% ethylacetate in dichloromethane to afford thebis(3-hydroxy-3-methyl-but-1-ynyl) fuctionalized triptycene (3.03 g,92%).

EXAMPLE 37 Synthesis of6,14-di-tert-butyl-1,4-diethynyl-[1′,2′]benzenoanthracene

6,14-di-tert-butyl-1,4-diethynyl-[1′,2′]benzenoanthracene 48 isillustrated in FIG. 9F.6,14-di-tert-butyl-1,4-bis(3-hydroxy-3-methyl-but-1-ynyl)-[1′,2′]benzenoanthracene47 (3.0 g, 5.66 mmol) was dissolved in toluene (200 ml) and degassed. Asolution of KOH (2.0 g) in methanol (20 ml) was added. The reaction washeated to 120° C. for 1.5 hours, cooled to room temperature and filteredthrough a plug of silica gel, rinsed with dichloromethane. The solventwas removed, and the residue was purified by flash chromatography toafford the diethynyltriptycene as a white solid (2.26 g, 96%).

EXAMPLE 38 Synthesis of6,14-di-tert-butyl-1,4-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl-ethenyl)-[1′,2′]benzeno-anthracene

6,14-di-tert-butyl-1,4-bis(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl-ethenyl)-[1′,2′]benzeno-anthracene49 is illustrated in FIG. 9F.6,14-di-tert-butyl-1,4-diethynyl-[1′,2′]benzenoanthracene 48 (1.00 g,1.79 mmol), and 4,4,5,5-tetramethyl-1,3,2-dioxoborolane (0.80 ml, 0.71g, 5.52 mmol) was dissolved in dry toluene (10 ml). The reaction washeated to 90° C. for 24 hours and the solvent was removed in vacuo.Flash chromatography eluting with 1:4, hexane:dichloromethane affordedthe bisborolane (727 mg, 50%).

EXAMPLE 39

Two nematic liquid crystals,1-(trans-4-hexylcyclohexyl)-4-isothiocyanatobenzene (“6CHBT,” Tm=12.4°C., TNI=42.4° C.), and 4-(trans-4-pentyl-cyclohexyl)benzonitrile(“5PCH,” Tm=30° C., TNI=55° C.), were tested for solubilizing thepolymers of one embodiment of the invention. Polymer PPVs withtert-butyl substitutions 53 and 55 in FIG. 9G could form homogeneoussolution in both liquid crystals while PPVs 52 and 54 were less soluble.To test the alignment of the polymer in liquid crystals, the solutionswere loaded to liquid crystal cells where the internals coated withparallel-orientated polyimide. At the central area of the internals wereimbedded thin layers of conducting indium tin oxide.

Absorption spectra were recorded in both parallel and orthogonaldirections relative to the expected alignment of the liquid crystalsthrough a polarizer. The absorption along the director of the polyimideon the surface was found to be much stronger, indicating that the longaxes (coinciding with the direction of the most probable electronictransition) of the polymers were orientated with the liquid crystalsparallel to the polyimide direction. It was observed that the polymer 55in 6CHBT in a liquid crystal cell preferred to align along with theliquid crystal, and the ordering parameter of transition moment of 6CHBTwas found to be 0.69.

When a voltage (9 V) was applied across the cell through the conductiveindium tin oxide coating, it was found that the absorption along thepolyimide direction was significantly diminished. This indicated achange of the orientation of the polymer long axis as a result of changeof the liquid crystal director under electric field, from parallel tothe surface to perpendicular to the surface. As a result, lessabsorption of light takes place because the electric vector of the lightcoming across the cell is mostly parallel to the surface, interactingpreferably with polymers with transition moments aligned parallel to thesurface. The absorption along the polyimide direction decreased when thecell was heated up across the nematic-isotropic transition temperatureof the liquid crystal.

The liquid crystal cells loaded with PPV solutions in both liquidcrystals were highly fluorescent under ultraviolet (“UV”) light, and thefluorescence was found to be highly polarized. Upon the application of avoltage of 9 V across the cell, the fluorescence was significantlydiminished due to less absorption of light resulted from thereorientation of the polymer long axis along the electric field. Theswitch was reversible, i. e., the fluorescence recovered when thevoltage was removed. Fluorescence spectra of the liquid crystal cellloaded with a solution of compound 55 in 6CHBT showed that the emissionmaximum of the liquid crystal solution shifted slightly to the red,relative to the emission from solution, due to induced alignment of thepolymer long axis parallel to the surface of the cell.

While several embodiments of the invention have been described andillustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and structures for performing thefunctions and/or obtaining the results or advantages described herein,and each of such variations or modifications is deemed to be within thescope of the present invention. More generally, those skilled in the artwould readily appreciate that all parameters, dimensions, materials, andconfigurations (list modified as appropriate) described herein are meantto be exemplary and that actual parameters, dimensions, materials, andconfigurations will depend upon specific applications for which theteachings of the present invention are used. Those skilled in the artwill recognize, or be able to ascertain using no more than routineexperimentation, many equivalents to the specific embodiments of theinvention described herein. It is, therefore, to be understood that theforegoing embodiments are presented by way of example only and that,within the scope of the appended claims and equivalents thereto, theinvention may be practiced otherwise than as specifically described. Thepresent invention is directed to each individual feature, system,material and/or method described herein. In addition, any combination oftwo or more such features, systems, materials and/or methods, if suchfeatures, systems, materials and/or methods are not mutuallyinconsistent, is included within the scope of the present invention. Inthe claims, all transitional phrases or phrases of inclusion, such as“comprising,” “including,” “carrying,” “having,” “containing,” and thelike are to be understood to be open-ended, i.e. to mean “including butnot limited to.” Only the transitional phrases or phrases of inclusion“consisting of” and “consisting essentially of” are to be interpreted asclosed or semi-closed phrases, respectively, as set forth in MPEPsection 2111.03.

TABLE 1 Results of polymerizations of 616 Other mono- Entry Compound merConditions^(a) Mn pdi 1 Fast − 616 none 200° C.^(b) 3,200 2.4 2 Slow −616 none 200° C.^(b) 4,700 2.3 3 ″ none 250° C., 30 min. 5,000 2.4 4Fast + Slow − 616 none 250° C., 60 min. 5,500 2.4 5 ″ none 250° C., 4hrs.  5,000^(c) 2.4 6 Fast − 616 620 (3 250° C., 2 hrs.  4,500^(c) 2.5wt. %) 7 Fast − 616 620, 250° C., 2 hrs.  4,900^(c) 3.2 621 (3 wt. %each) 8 ″ none 0.1M in decalin 2,500 1.4 250° C., 72 hrs. 9 Slow − 616none 0.1M in decalin 2,100 1.4 250° C., 72 hrs. 10 Fast + Slow − 616none 225° C., 1 hr. 5,600 2.2 11 ″ none 190° C., 40 min. 3,000 2.4 12 ″none 1.0M in m-cresol 3,700 2.1 200° C., 4 hrs. 13 ″ none 2.0M inm-cresol 4,000 2.1 14 ″ none 2.0M in eicosane 4,200 2.1 235° C., 2 hrs.15 ″ none 1.0M in eicosane 4,400 2.5 250° C., 4 hrs. 16 ″ none 0.5M ineicosane 3,600 2.2 250° C., 19 hrs. 17 ″ none 1.0M in hexadecane 4,4001.8 170° C., 20 hrs. 18 ″ none 1.0M in hexadecane 3,600 1.9 140° C., 20hrs. ^(a)Solid phase reactions unless otherwise noted ^(b)Heated to 200°C. and then immediately cooled ^(c)THF soluble fraction only

TABLE 2 Dichroic ratios for 24–26 in aligned hosts^(a) Long-AxisShort-Axis Compound, Host A_(//)/A_(⊥) A_(//)/A_(⊥) 24, LC — 0.66^(b)24, PVC 1.04 0.93^(b) 25, LC — 1.80 25, PVC 0.83 1.56 26, LC — 2.34 26,PVC 0.77 1.56 ^(a)UV maxima for each dichroic ratio measurement were(Long-Axis, Short-Axis/nm): 24 (257, 381), 25 (263, 379), 26 (282, 383).^(b)For direct comparison of absorption intensities with 25 and 26, theinverse of these ratios should be taken. For LC, A_(⊥)/A_(//) = 1.52;PVC A_(⊥)/A_(//) = 1.07; note these are both smaller than values for 25and 26 in all cases.

TABLE 3 Order parameters (S_(ob)) for 0, 27–32 Compound S_(ob) % Change0 0.60 — 27 0.65  +9% 28 0.69 +15% 29 0.76 +27% 30 0.57  −5% 31 0.60 —32 0.65  +9%

1. A composition, comprising: a ladder polymer or ladder oligomer, saidladder polymer or oligomer comprising an iptycene, wherein the ladderpolymer or oligomer is a polymer or oligomer having a backbone that canonly be severed by breaking at least two bonds.
 2. A composition as inclaim 1, having a molecular weight in excess of 2000 daltons, comprisinga shape persistent molecule containing bridgehead atoms, with molecularstructures radiating from the bridgehead atoms in three directions andextending outwardly therefrom such that each defines a van der Waalscontact of furthest point from the bridgehead atoms of no less than 3.5Å, the composition having a dielectric constant of less than 3.0.
 3. Acomposition as in claim 2, comprising a linear polymer comprising aniptycene.
 4. A composition as in claim 2, arranged as a dielectricmaterial in an electronic component.
 5. A composition as in claim 2,wherein the molecular structures that radiate from the bridgehead atomsextend outwardly therefrom such that each defines a van der Waalscontact of furthest point from the bridgehead atoms of no less than 4.0Å.
 6. A composition as in claim 2, wherein the molecular structures thatradiate from the bridgehead atoms extend outwardly therefrom such thateach defines a van der Waals contact of furthest point from thebridgehead atoms of no less than 4.5 Å.
 7. A composition as in claim 2,wherein the molecular structures that radiate from the bridgehead atomsextend outwardly therefrom such that each defines a van der Waalscontact of furthest point from the bridgehead atoms of no less than 5.0Å.
 8. A composition as in claim 2, wherein the molecular structures thatradiate from the bridgehead atoms extend outwardly therefrom such thateach defines a van der Waals contact of furthest point from thebridgehead atoms of no less than 5.5 Å.
 9. A composition as in claim 2,wherein the molecular structures that radiate from the bridgehead atomsextend outwardly therefrom such that each defines a van der Waalscontact of furthest point from the bridgehead atoms of no less than 6.0Å.
 10. A composition as in claim 2, wherein the molecular structuresthat radiate from the bridgehead atoms extend outwardly therefrom suchthat each defines a van der Waals contact of furthest point from thebridgehead atoms of no less than 6.2 Å.
 11. A composition as in claim 1,having a lowest energy state in which the polymer has a backbone thecontains a plane.
 12. A composition as in claim 11, including aplurality of aromatic rings that each align normal to the plane in thelowest energy state, and the polymer has a minimum dimension, measuredas van der Waals contact dimensions, of 6.0 Å.
 13. A composition as inclaim 1, the polymer including a backbone comprising backbone atomsbonded to other backbone atoms, wherein bonds involving the backboneatoms are not freely rotatable.
 14. A composition as in claim 1,comprising a structure:

wherein A, G, H, I, and J are aromatic groups: c is less than 10,000;d=1, 2, and d¹=0, 1, such that when d¹=0, d²=0 and when d¹=1, d²=0 or 1.15. A composition as in claim 2, wherein the bridgehead atoms comprisecarbon or nitrogen.
 16. A composition as in claim 1 where in thebackbone is composed of triptycene units.
 17. A composition as in claim2 comprising a branched structure.
 18. A composition as in claim 2comprising a hyperbranched structure.
 19. A composition as in claim 18,comprising polymer chain units comprising chemical functionalityallowing formation of grafts.
 20. A composition as in claim 18,comprising a grafted polymer including non-iptycene units grafted ontopolymer chain units.
 21. A composition as in claim 18, comprising agrafted polymer including iptycene units grafted onto polymer chainunits.
 22. A composition as in claim 18, comprising a polymer of monomerunits each including two reactive sites, one of which has reacted withanother monomer unit to form the polymer backbone, and another of whichis available for grafting after formation of the polymer.
 23. Acomposition as in claim 1 comprising a dendritic structure.
 24. Acomposition as in claim 1 wherein the polymer has cyclic sub-units. 25.A composition as in claim 1 which, in a solid state, has at least 30%free volume and a dielectric constant of about 1.9 or less.
 26. Acomposition as in claim 1 which, in a solid state, has at least 50% freevolume and a dielectric constant of about 1.7 or less.
 27. A compositionas in claim 1 which, in a solid state, has at least 70% free volume anda dielectric constant of about 1.5 or less.
 28. A composition as inclaim 1 which, in a solid state, has at least 90% free volume and adielectric constant of about 1.2 or less.
 29. A composition as in claim2 wherein the polymer has a backbone defined by non-iptycene units, andcomprises iptycene units connected to the backbone.
 30. A composition asin claim 1, comprising a first porous polymeric component and furthercomprising a second polymeric component forming an interpenetratingnetwork permeating the pores of the first porous polymeric component.31. A composition comprising a first, porous, shape persistent polymerand a second, flexible polymer forming an interpenetrating network, thesecond polymer permeating the pores of the first polymer, wherein thefirst polymer and the second polymer have different structures and arenot covalently bound to each other.
 32. A composition as in claim 31wherein the second component is an elastomer.
 33. A composition as inclaim 31 wherein the second component is a conjugated polymer.
 34. Acomposition as in claim 31 wherein the material shows a negativePoisson's ratio when elongated.
 35. A device comprising: a chromophore;and a shape-persistent molecule having at least 20% free volume; thedevice constructed and arranged to be capable of moving the chromophorefrom a first orientation to a second orientation upon application to thechromophore of a source of external energy, wherein the source ofexternal energy is an electric, magnetic, optical, acoustic,electromagnetic, or mechanical field.
 36. A device as in claim 35,wherein the device is constructed and arranged to change thepolarization of the chromophore's optical, magnetic, or dielectricabsorptions upon application of the external energy source.
 37. A deviceas in claim 35, constructed and arranged to display a change in colorupon application of the external energy source.
 38. A device as in claim35, constructed and arranged to display a change in luminescence uponapplication of the external energy source.
 39. A device as in claim 35,constructed and arranged to display a change in transmission of anoptical signal upon application of the external energy source.
 40. Adevice as in claim 35, wherein the chromophore bonded to theshape-persistent molecule can be switched from a first low-energy,stable orientation to a second, low-energy, stable orientation uponapplication of the external energy source.
 41. A device as in claim 35,constructed and arranged to impart polymerization to the iptycene uponapplication of the external energy source.
 42. A device as in claim 35,constructed and arranged to display a signal recognizable to a humanupon application of the external energy source.
 43. A device as in claim42, wherein the signal is a hologram.
 44. A device as in claim 35,wherein application of the external energy source causes switching in aliquid crystal display.
 45. A device as in claim 35, wherein theshape-persistent molecule comprises an iptycene.
 46. A device as inclaim 35, wherein the chromophore is bonded to the shape-persistentmolecule.